Host and parasite hi-res stock photography and images - Page 28

Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients Stock Photo

RFWBE7HA–Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients

. Commercial mass culture of the California red scale parasite : Aphytis lignanensis. Citrus; Scale insects. laboratory in the control of a pest-para- site population in the oleander-scale culture during an eradication program. The immediate and residual effects of pyrethrum on oleander scale. Aspidioti- phagus sp. (the contaminant), and on the host plant (banana squash) have been investigated. The pyrethrum source was a commercial aerosol bomb which util- ized soybean oil as the carrier and freon as the propellant. Dosage was measured in the number of seconds during which the aerosol was perm Stock Photo

RMREGHNF–. Commercial mass culture of the California red scale parasite : Aphytis lignanensis. Citrus; Scale insects. laboratory in the control of a pest-para- site population in the oleander-scale culture during an eradication program. The immediate and residual effects of pyrethrum on oleander scale. Aspidioti- phagus sp. (the contaminant), and on the host plant (banana squash) have been investigated. The pyrethrum source was a commercial aerosol bomb which util- ized soybean oil as the carrier and freon as the propellant. Dosage was measured in the number of seconds during which the aerosol was perm

RF2AKT3N1–Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients

. Animal parasites and parasitic diseases. Domestic animals; Veterinary medicine. PARASITOLOGY. 41 whose quarters are separated only by a partition, may get upon horses and cattle and cause temporary parasitism. Each parasite has its own host or hosts and will not live permanently upon another. Lice of Birds. The Large Hen Louse.—^Menopon Biseriatum. This is the largest louse found upon the hen. It is about one-twelfth of an inch in length, light in color, with mouth parts arranged for mastication as illustrated in Fig. 10. The free extremities of the legs are provided with booklets which aid Stock Photo

RMRN5360–. Animal parasites and parasitic diseases. Domestic animals; Veterinary medicine. PARASITOLOGY. 41 whose quarters are separated only by a partition, may get upon horses and cattle and cause temporary parasitism. Each parasite has its own host or hosts and will not live permanently upon another. Lice of Birds. The Large Hen Louse.—^Menopon Biseriatum. This is the largest louse found upon the hen. It is about one-twelfth of an inch in length, light in color, with mouth parts arranged for mastication as illustrated in Fig. 10. The free extremities of the legs are provided with booklets which aid

RFWBE7WC–Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients

. The British rust fungi (Uredinales) their biology and classification. Rust fungi. 58 MELAMPSORA PINITORQUA point, combined with this lateral curvature, causes S-shaped distortions which have given rise to the name " Pine Branch Twist" for the disease (Fig. 35). It is suggested by Massee that the secidiospores can repro- duce the sec.idia and thus propagate the parasite on the Pine without reference to the alternate host, but no proof is given of this statement. The mycelium is almost certainly perennial in the affected branch, and thus fresh outbreaks arise year by year more or les Stock Photo

RMRE388J–. The British rust fungi (Uredinales) their biology and classification. Rust fungi. 58 MELAMPSORA PINITORQUA point, combined with this lateral curvature, causes S-shaped distortions which have given rise to the name " Pine Branch Twist" for the disease (Fig. 35). It is suggested by Massee that the secidiospores can repro- duce the sec.idia and thus propagate the parasite on the Pine without reference to the alternate host, but no proof is given of this statement. The mycelium is almost certainly perennial in the affected branch, and thus fresh outbreaks arise year by year more or les

RFWHAH51–Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients

. Botany, an elementary text for schools. Botany. 184 STUDIES IN CRYPTOGAMS. 325. iori containing teleu- tospores of wheat true parasite, affecting wheat and a few other grasses. The mycelium here cannot be seen by the unaided eye, for it consists of threads whieli are present within the host plant, mostly in the intercellular spaces. These threads also send short branches, or haustoria (180), into the neighboring cells to absorb nutriment. The resting-spores of wheat rust are produced in late summer, when they may be found in black lines breaking through the epidermis of the wheat-stalk. They Stock Photo

RMRH9472–. Botany, an elementary text for schools. Botany. 184 STUDIES IN CRYPTOGAMS. 325. iori containing teleu- tospores of wheat true parasite, affecting wheat and a few other grasses. The mycelium here cannot be seen by the unaided eye, for it consists of threads whieli are present within the host plant, mostly in the intercellular spaces. These threads also send short branches, or haustoria (180), into the neighboring cells to absorb nutriment. The resting-spores of wheat rust are produced in late summer, when they may be found in black lines breaking through the epidermis of the wheat-stalk. They

RFWKDTG1–Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients

. Animal parasites and human disease. Parasites; Medical parasitology; Insects as carriers of disease. DWARF TAPEWORM 243 by the armed head, and become adult. It is said that eggs of this parasite can be found in the faeces within a month after an egg of the preceding generation has been swallowed. Self- infection with these eggs rarely occurs, since the eggs will not develop unless acted upon by the gastric juices. There is still room for doubt as to whether an insect is not commonly involved as an intermediate host as in other species of Hymenolepis; in fact, several investigators have found Stock Photo

RMRN5246–. Animal parasites and human disease. Parasites; Medical parasitology; Insects as carriers of disease. DWARF TAPEWORM 243 by the armed head, and become adult. It is said that eggs of this parasite can be found in the faeces within a month after an egg of the preceding generation has been swallowed. Self- infection with these eggs rarely occurs, since the eggs will not develop unless acted upon by the gastric juices. There is still room for doubt as to whether an insect is not commonly involved as an intermediate host as in other species of Hymenolepis; in fact, several investigators have found

RFWBE774–Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients

. Common Illinois insects : and why they are interesting. Insects -- Illinois. Saddle-back {Sibine stimulea) destroyed by parasites. Millions of destructive caterpillars are victims of parasitic wasps whose larvae grow inside body and emerge to spin cocoons. (3x) Parasites differ from the preda- tors in that they enter the body of the victim, called the host, feeding on blood or tissues until full grown. By this time the host is dead or nearly so, and the parasite trans- forms to adult which mates and lays its Qgg on another victim. The long "sting" ou the body of the Long- tailed Me Stock Photo

RMREFM66–. Common Illinois insects : and why they are interesting. Insects -- Illinois. Saddle-back {Sibine stimulea) destroyed by parasites. Millions of destructive caterpillars are victims of parasitic wasps whose larvae grow inside body and emerge to spin cocoons. (3x) Parasites differ from the preda- tors in that they enter the body of the victim, called the host, feeding on blood or tissues until full grown. By this time the host is dead or nearly so, and the parasite trans- forms to adult which mates and lays its Qgg on another victim. The long "sting" ou the body of the Long- tailed Me

RF2C48AX1–Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients

. The animals and man; an elementary textbook of zoology and human physiology. Zoology; Physiology. 414 THE ANIMALS AND MAN digested in the intestine of its host. It has no eyes or other special sense-organs, nor any organ of locomotion. Thus its body is very degenerate. The life-history of the tapeworm is interesting, because it lives in two hosts during its life. The eggs of this parasite pass from the intestine with the excreta, and to develop must. : v',7 Fig. 206. Trichina spiralis, encysted in muscle of a pig. (Greatly en- larged.) be taken into the body of some other animal. In the case Stock Photo

RMRDT33C–. The animals and man; an elementary textbook of zoology and human physiology. Zoology; Physiology. 414 THE ANIMALS AND MAN digested in the intestine of its host. It has no eyes or other special sense-organs, nor any organ of locomotion. Thus its body is very degenerate. The life-history of the tapeworm is interesting, because it lives in two hosts during its life. The eggs of this parasite pass from the intestine with the excreta, and to develop must. : v',7 Fig. 206. Trichina spiralis, encysted in muscle of a pig. (Greatly en- larged.) be taken into the body of some other animal. In the case

RF2AF890A–Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients

. Botany of the living plant. Botany. ir-:,REGULAR NUTRITION 193. Fig. 144. Median section of a young plant of Orobanche seated upon tlie root of its host. (After Hovelacque.) ( x 20.) and cortex, thus tapping both storage and conducting tissues. Where the sucker impinges upon a vascular strand a continuous xylem- connection may be established ; in the phloem also a close relation of the sieve- tubes of the parasite with those of the host has been shown. The Broomrape [Orobanche), and the Toothwort (Lalhraea) are further examples of parasites with complete physiologi- cal dependence. Both of t Stock Photo

RMRDY8EP–. Botany of the living plant. Botany. ir-:,REGULAR NUTRITION 193. Fig. 144. Median section of a young plant of Orobanche seated upon tlie root of its host. (After Hovelacque.) ( x 20.) and cortex, thus tapping both storage and conducting tissues. Where the sucker impinges upon a vascular strand a continuous xylem- connection may be established ; in the phloem also a close relation of the sieve- tubes of the parasite with those of the host has been shown. The Broomrape [Orobanche), and the Toothwort (Lalhraea) are further examples of parasites with complete physiologi- cal dependence. Both of t

RFWBE6DD–Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients

. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. PARASITES OF GIPSY-MOTH CATERPILLARS. 189. Fig. 28.—Apanteles solitarius: Adult female and cocoon, larged. (Original.) En- On the other hand, studies with the parasites of native insects have revealed the existence of what may be called accidental or incidental parasites. These may be important parasites of one insect and of no importance whatever in connection with another, nearly allied. Sometimes this is due to the fact that the one species of host may excite in the mother parasite the desire to oviposit, whic Stock Photo

RMRGWK4G–. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. PARASITES OF GIPSY-MOTH CATERPILLARS. 189. Fig. 28.—Apanteles solitarius: Adult female and cocoon, larged. (Original.) En- On the other hand, studies with the parasites of native insects have revealed the existence of what may be called accidental or incidental parasites. These may be important parasites of one insect and of no importance whatever in connection with another, nearly allied. Sometimes this is due to the fact that the one species of host may excite in the mother parasite the desire to oviposit, whic

RFWP5YHM–Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients

RMRGW44E–. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. PARASITES OF GIPSY-MOTH CATERPILLARS. 189. Fig. 28.—Apanteles solitarius: Adult female and cocoon, larged. (Original.) En- On the other hand, studies with the parasites of native insects have revealed the existence of what may be called accidental or incidental parasites. These may be important parasites of one insect and of no importance whatever in connection with another, nearly allied. Sometimes this is due to the fact that the one species of host may excite in the mother parasite the desire to oviposit, whic

RFWNGCD4–Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients

. Botany for high schools. Botany. CHAPTER XV. NUTRITION OF PARASITES AND SAPROPHYTES. 207. A parasite is an organism, plant or animal, which lives on or in another living organism at its expense, deriving all or a part of its nourishment from it. The plant or animal on which the parasite lives is called the ^' host." The parasite derives a part or all of its food from its host, usually inflicting more or less injury upon the host or even causing its death. Parasitic plants are represented in nearly all the great branches of the plant king- dom. There are some among the flower- ing plants Stock Photo

RMRH94ND–. Botany for high schools. Botany. CHAPTER XV. NUTRITION OF PARASITES AND SAPROPHYTES. 207. A parasite is an organism, plant or animal, which lives on or in another living organism at its expense, deriving all or a part of its nourishment from it. The plant or animal on which the parasite lives is called the ^' host." The parasite derives a part or all of its food from its host, usually inflicting more or less injury upon the host or even causing its death. Parasitic plants are represented in nearly all the great branches of the plant king- dom. There are some among the flower- ing plants

RF2BH3315–Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients

. Better fruit. Fruit-culture. COMPLETE COVERING WITH THE MILDEW Bud that was infected after making a healthy start in the spring few short feeders that draw substance from the plant. The apple powdery mildew is no excep- tion to this general rule. The parasite grows over the surface of the affected portions of the host, and so far as the observations of the writer go it has a very limited internal system. The exter- nal growth of the fungus is, however, very profuse, and affords a very ready means of recognition. This mildew often BETTER FRUIT completely covers the surface of young shoots, an Stock Photo

RMRHTF1D–. Better fruit. Fruit-culture. COMPLETE COVERING WITH THE MILDEW Bud that was infected after making a healthy start in the spring few short feeders that draw substance from the plant. The apple powdery mildew is no excep- tion to this general rule. The parasite grows over the surface of the affected portions of the host, and so far as the observations of the writer go it has a very limited internal system. The exter- nal growth of the fungus is, however, very profuse, and affords a very ready means of recognition. This mildew often BETTER FRUIT completely covers the surface of young shoots, an

RF2B1A207–Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients

. Principles of modern biology. Biology. 180 - The Cell A parasite may be neutral with reference to one kind of host, but definitely patho- genic to another. Such a case is provided by Cryptocotyle, a parasitic flatworm. The usual host of Cryptocotyle is a seagull, and adult gulls are quite immune to the presence of the parasite in their intestine. But mammals, such as the dog and fox, may become seri- ously ill when they are infected with Crypto- cotyle. Natural immunity depends to a large ex- tent upon the capacity of the host's tissues to form antibody substances (pp. 335 and 336). These an Stock Photo

RMRDXY5R–. Principles of modern biology. Biology. 180 - The Cell A parasite may be neutral with reference to one kind of host, but definitely patho- genic to another. Such a case is provided by Cryptocotyle, a parasitic flatworm. The usual host of Cryptocotyle is a seagull, and adult gulls are quite immune to the presence of the parasite in their intestine. But mammals, such as the dog and fox, may become seri- ously ill when they are infected with Crypto- cotyle. Natural immunity depends to a large ex- tent upon the capacity of the host's tissues to form antibody substances (pp. 335 and 336). These an

RFWPMX2E–Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients

. Bulletin of the U.S. Department of Agriculture. Agriculture; Agriculture. a ' c * "" h Fig. 17.—Dibrachys boucheanus: a, Larva; 6, pupa; c, adult female; d, head of larva; e, antenna or male, highly magnified. Greatly enlarged. (After Howard.) joTiannseni and CJielonus sJiosJioneanorum, the former seeming to be its favorite host. This species was reared from the egg in the laboratory,, where it attacked the mature larvse of its hosts after they had spun their cocoons. Where the cocoons were not too thick to prevent it from reaching its host the parasite would often feed at the woun Stock Photo

RMRGC73M–. Bulletin of the U.S. Department of Agriculture. Agriculture; Agriculture. a ' c * "" h Fig. 17.—Dibrachys boucheanus: a, Larva; 6, pupa; c, adult female; d, head of larva; e, antenna or male, highly magnified. Greatly enlarged. (After Howard.) joTiannseni and CJielonus sJiosJioneanorum, the former seeming to be its favorite host. This species was reared from the egg in the laboratory,, where it attacked the mature larvse of its hosts after they had spun their cocoons. Where the cocoons were not too thick to prevent it from reaching its host the parasite would often feed at the woun

RFWW8DAJ–Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients

. Lessons in botany. Botany. HOW PLANTS OBTAIN FOOD. 89 ing nutriment maybe demonstrated by making sections through both parasite and host at a point where the haustoria enter the stem. These should then be mounted for examination with the microscope. Fig. 64. Several teleutospores, showing the variations in form. 161. Carnivorous plants, or insectivorous plants.—Examples of these are the well-known Venus fly-trap (Dionaea muscipula) and the sundew (Drosera rotundifolia). These are illustrated in figures 67 and 68. The lamina of the leaf of the Venus. Fig. 65. Cells from the stem of a rusted c Stock Photo

RMRDDAC6–. Lessons in botany. Botany. HOW PLANTS OBTAIN FOOD. 89 ing nutriment maybe demonstrated by making sections through both parasite and host at a point where the haustoria enter the stem. These should then be mounted for examination with the microscope. Fig. 64. Several teleutospores, showing the variations in form. 161. Carnivorous plants, or insectivorous plants.—Examples of these are the well-known Venus fly-trap (Dionaea muscipula) and the sundew (Drosera rotundifolia). These are illustrated in figures 67 and 68. The lamina of the leaf of the Venus. Fig. 65. Cells from the stem of a rusted c

RFWWBH3B–Dodder Genus Cuscuta is The parasite wraps the stems of plant cultures with yellow threads and sucks out the vital juice and nutrients

. Goldfish breeds and other aquarium fishes, their care and propagation; a guide to freshwater and marine aquaria, their fauna, flora and management. Aquariums; Goldfish. FIG. 96 Trichoditia pediculus a Hirudinld parasite. Greatly enlarged. its host; and produces tiny red external, gill and throat ulcers into which it is pitted like a cancer. When present in numbers it is a dangerous parasite and has been found on fishes afflicted with what is popularly known as Twitters. It has a nearly circular ciliated body and on its lower side a suctoral disc. Arachnia or Arachnid Parasites. This group in Stock Photo

RMRDYXMX–. Goldfish breeds and other aquarium fishes, their care and propagation; a guide to freshwater and marine aquaria, their fauna, flora and management. Aquariums; Goldfish. FIG. 96 Trichoditia pediculus a Hirudinld parasite. Greatly enlarged. its host; and produces tiny red external, gill and throat ulcers into which it is pitted like a cancer. When present in numbers it is a dangerous parasite and has been found on fishes afflicted with what is popularly known as Twitters. It has a nearly circular ciliated body and on its lower side a suctoral disc. Arachnia or Arachnid Parasites. This group in

Dodder (Genus Cuscuta) is a parasitic plant Set of four photos Stock Photo

RFM5R172–Dodder (Genus Cuscuta) is a parasitic plant Set of four photos

. Annals of the Entomological Society of America. Entomology. 1918] Wax Moth Parasite 177 the proper position, and then released. The eggs are not fastened, but he loosely in the folds of the skin of the host. The eggs hatch in from 3 to 7 days and the young parasites immediately fasten themselves to the body of the host and begin to feed. The length of the larval stage was found to be rather variable, lasting from two to four weeks or even longer. Without exception, the moth larva was attacked by bacteria and reduced, before the parasite larvae completed their growth, to a putrescent semi-liq Stock Photo

RMRMR6JM–. Annals of the Entomological Society of America. Entomology. 1918] Wax Moth Parasite 177 the proper position, and then released. The eggs are not fastened, but he loosely in the folds of the skin of the host. The eggs hatch in from 3 to 7 days and the young parasites immediately fasten themselves to the body of the host and begin to feed. The length of the larval stage was found to be rather variable, lasting from two to four weeks or even longer. Without exception, the moth larva was attacked by bacteria and reduced, before the parasite larvae completed their growth, to a putrescent semi-liq

. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. DWARF TAPEWORM 243 by the armed head, and become adult. It is said that eggs of this parasite can be found in the faeces within a month after an egg of the preceding generation has been swallowed. Self- infection with these eggs rarely occurs, since the eggs will not develop unless acted upon by the gastric juices. There is still room for doubt as to whether an insect is not commonly involved as an intermediate host as in other species of Hymenolepis; in fact, several investigators have found cysticerco Stock Photo

RMRD9K5F–. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. DWARF TAPEWORM 243 by the armed head, and become adult. It is said that eggs of this parasite can be found in the faeces within a month after an egg of the preceding generation has been swallowed. Self- infection with these eggs rarely occurs, since the eggs will not develop unless acted upon by the gastric juices. There is still room for doubt as to whether an insect is not commonly involved as an intermediate host as in other species of Hymenolepis; in fact, several investigators have found cysticerco

. Bulletin of the U.S. Department of Agriculture. Agriculture; Agriculture. 40 BULLETIN 427, U. S. DEPARTMENT OF AGEICULTURE. larva has been parasitized it does not pupate, but soon breaks down and becomes semiliquid. The mature larva spins a light but tough white cocoon within the cocoon of its host, thus being well protected. This apparently. Fig. 29.— Chelonus shoshoneanorum: Adult female. Much enlarged. (Original.) explains its comparative immunity from the secondary parasite Dibrachys houcheanus. The adult feeds quite often at the oviposition wounds of its host. The adults are very hardy Stock Photo

RMRGC6YY–. Bulletin of the U.S. Department of Agriculture. Agriculture; Agriculture. 40 BULLETIN 427, U. S. DEPARTMENT OF AGEICULTURE. larva has been parasitized it does not pupate, but soon breaks down and becomes semiliquid. The mature larva spins a light but tough white cocoon within the cocoon of its host, thus being well protected. This apparently. Fig. 29.— Chelonus shoshoneanorum: Adult female. Much enlarged. (Original.) explains its comparative immunity from the secondary parasite Dibrachys houcheanus. The adult feeds quite often at the oviposition wounds of its host. The adults are very hardy

. Annual report of the Cornell University Agricultural Experiment Station, Ithaca, N.Y. Cornell University. Agricultural Experiment Station; Agriculture -- New York (State). Photo. Nov. 2, 1908 Fig. 51.—Photomicrograph of a pycnidiimi. The spores stream out through the opening at the apex. Original Fig. 52.—Drawing to show relation of parasite to host, compound pycnidium, germinated spores, and paraphyses. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectl Stock Photo

RMRM8C86–. Annual report of the Cornell University Agricultural Experiment Station, Ithaca, N.Y. Cornell University. Agricultural Experiment Station; Agriculture -- New York (State). Photo. Nov. 2, 1908 Fig. 51.—Photomicrograph of a pycnidiimi. The spores stream out through the opening at the apex. Original Fig. 52.—Drawing to show relation of parasite to host, compound pycnidium, germinated spores, and paraphyses. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectl

. Outlines of plant life : with special reference to form and function . Botany. SYMBIOSIS. 257 C. Parasitism. 369. I. Fungi.—A very large number of colorless plants have adapted themselves to live upon living plants or ani- mals which they force to act as their unwilling hosts. By the presence of the parasite the normal functions of the host or its normal growth or both are more or less seriously inter- fered with, so as to produce disease, slight or grave, local or general, accord- ing to the circum- stances. Many ani- mals are thus preyed upon by bacteria and fungi. Most communicable diseas Stock Photo

RMRDHNCT–. Outlines of plant life : with special reference to form and function . Botany. SYMBIOSIS. 257 C. Parasitism. 369. I. Fungi.—A very large number of colorless plants have adapted themselves to live upon living plants or ani- mals which they force to act as their unwilling hosts. By the presence of the parasite the normal functions of the host or its normal growth or both are more or less seriously inter- fered with, so as to produce disease, slight or grave, local or general, accord- ing to the circum- stances. Many ani- mals are thus preyed upon by bacteria and fungi. Most communicable diseas

$. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. 2^4 REMEDIES arc still commonly attacked, they do not appear to suffer appreciably. Artificial co)iirol of fmigal diseases is accomplished by diverse means, but in each case success depends upon a knowledge of the life-history of the parasite. The method of treatment varies according as the parasite attacks the overground or underground organs of the host. Several of the Fungi considered in the last chapter {e.g. Potato Blight) afford instances of the former mode of attack. Diseases of the subter- ranean part Stock Photo$

RMRDWPJD–. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. 2^4 REMEDIES arc still commonly attacked, they do not appear to suffer appreciably. Artificial co)iirol of fmigal diseases is accomplished by diverse means, but in each case success depends upon a knowledge of the life-history of the parasite. The method of treatment varies according as the parasite attacks the overground or underground organs of the host. Several of the Fungi considered in the last chapter {e.g. Potato Blight) afford instances of the former mode of attack. Diseases of the subter- ranean part

. [Bulletins on forest pathology : from Bulletin U.S.D.A., Washington, D.C., 1913-1925]. Trees; Plant diseases. LARCH MISTLETOE. 9 The infected wood of the branch, either at its base or other por- tions, where not too greatly enlarged by the stimulating effects of the parasite, requires a much smaller force to break it at the point of infection than is the case in normal branches of like age and thick- ness. The penetration and embedding of the vertical root system of the parasite in the wood of the host add nothing to the strength of the infected tissue, but diminish its normal strength when Stock Photo

RMRG900Y–. [Bulletins on forest pathology : from Bulletin U.S.D.A., Washington, D.C., 1913-1925]. Trees; Plant diseases. LARCH MISTLETOE. 9 The infected wood of the branch, either at its base or other por- tions, where not too greatly enlarged by the stimulating effects of the parasite, requires a much smaller force to break it at the point of infection than is the case in normal branches of like age and thick- ness. The penetration and embedding of the vertical root system of the parasite in the wood of the host add nothing to the strength of the infected tissue, but diminish its normal strength when

RMRN51M0–. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. DWARF TAPEWORM 243 by the armed head, and become adult. It is said that eggs of this parasite can be found in the faeces within a month after an egg of the preceding generation has been swallowed. Self- infection with these eggs rarely occurs, since the eggs will not develop unless acted upon by the gastric juices. There is still room for doubt as to whether an insect is not commonly involved as an intermediate host as in other species of Hymenolepis; in fact, several investigators have found cysticerco

. Diseases of domesticated birds. Poultry; Poultry; Birds. 202 DISEASES OF DOMESTICATED BIRDS the eyes a few drops of saturated solution of boric acid. Ransom recommends anointing the eyes with a mixture of lard 9 parts and iodoform, 1 part or with carbolized vaseline. Life history of the worm. Very little is known of the life his- tory of the parasite. It seems probable that the embryos pass a portion of their existence either free or in a secondary host. The reports of the presence of the worm in chickens are, so far as knoAvn, limited to sea coast regions. This suggests the possibility that Stock Photo

RMRE0DEJ–. Diseases of domesticated birds. Poultry; Poultry; Birds. 202 DISEASES OF DOMESTICATED BIRDS the eyes a few drops of saturated solution of boric acid. Ransom recommends anointing the eyes with a mixture of lard 9 parts and iodoform, 1 part or with carbolized vaseline. Life history of the worm. Very little is known of the life his- tory of the parasite. It seems probable that the embryos pass a portion of their existence either free or in a secondary host. The reports of the presence of the worm in chickens are, so far as knoAvn, limited to sea coast regions. This suggests the possibility that

. Minnesota plant diseases. Plant diseases. Minnesota Plant Diseases. 165 nest broom of the red cedar and the great bush- like brooms of the bal- sam fir. These have al- ready been described as stimulated portions of the host plant which, with the fungus parasite, live in partnership at the expense of the neighbor- ing parts of the host. Besides this deforming power of many rusts these parasites are injuri- ous in the stealing of nourishment which they accomplish at the ex- pense of the host and in the wounding of plant parts. The host, as a re- sult, becomes impover- ished and may finally en- Stock Photo

RMRDEXHB–. Minnesota plant diseases. Plant diseases. Minnesota Plant Diseases. 165 nest broom of the red cedar and the great bush- like brooms of the bal- sam fir. These have al- ready been described as stimulated portions of the host plant which, with the fungus parasite, live in partnership at the expense of the neighbor- ing parts of the host. Besides this deforming power of many rusts these parasites are injuri- ous in the stealing of nourishment which they accomplish at the ex- pense of the host and in the wounding of plant parts. The host, as a re- sult, becomes impover- ished and may finally en-

. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. 14 DECIDITOTJS FRUIT INSECTS AND INSECTICIDES. Thi'ips are in the ground all of this time, and for the most part within reach of the cultivator, but they mature and arrive on the trees in March and April, before spring cultivating is begun. NATURAL ENEMIES. The pear thrips is largely protected from ordinary preaaceous and parasitic insects, because it spends so long a time hidden away in the ground. A successfid parasite must in a way parallel the life of its host, and we have found no insect which thus follows t Stock Photo

RMRGTHFA–. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. 14 DECIDITOTJS FRUIT INSECTS AND INSECTICIDES. Thi'ips are in the ground all of this time, and for the most part within reach of the cultivator, but they mature and arrive on the trees in March and April, before spring cultivating is begun. NATURAL ENEMIES. The pear thrips is largely protected from ordinary preaaceous and parasitic insects, because it spends so long a time hidden away in the ground. A successfid parasite must in a way parallel the life of its host, and we have found no insect which thus follows t

. Fresh-water biology. Freshwater biology. PARASITIC ROUNDWORMS 545 pig finds its intermediate host in terrestrial beetle larvae. Of forms from aquatic Hosts it is inferred that the ripe embryos dis- charged into the water with the feces of the host attain by chance a suitable intermediate host which is probably a crustacean or in- sect and in that develop to the end of the larval stage. When this intermediate host is eaten by the final host the parasite reaches the place in which it can complete its development. Almost no records have been published of Acanthocephala from North American fresh Stock Photo

RMRDAWK2–. Fresh-water biology. Freshwater biology. PARASITIC ROUNDWORMS 545 pig finds its intermediate host in terrestrial beetle larvae. Of forms from aquatic Hosts it is inferred that the ripe embryos dis- charged into the water with the feces of the host attain by chance a suitable intermediate host which is probably a crustacean or in- sect and in that develop to the end of the larval stage. When this intermediate host is eaten by the final host the parasite reaches the place in which it can complete its development. Almost no records have been published of Acanthocephala from North American fresh

. Protozoo?logy. Protozoa; Protozoa, Pathogenic. 78 PHYSIOLOGICAL ACTIVITIES OF THE PROTOZOA plant and animal tissues, dissolved in the water. Other saprophytes live upon the juices in blood or other fluids of the animal body which are similarly taken in by osmosis; these, however, belong to the group of parasites or commensals, the difference between the two being largely one of degree only, a parasite exerting some deleterious effect upon the host, while a saprophyte and a commensal are harmless. In all such cases the protozoa multiply in the region, such as a water supply, or the fluids of Stock Photo

RMRDXBYH–. Protozoo?logy. Protozoa; Protozoa, Pathogenic. 78 PHYSIOLOGICAL ACTIVITIES OF THE PROTOZOA plant and animal tissues, dissolved in the water. Other saprophytes live upon the juices in blood or other fluids of the animal body which are similarly taken in by osmosis; these, however, belong to the group of parasites or commensals, the difference between the two being largely one of degree only, a parasite exerting some deleterious effect upon the host, while a saprophyte and a commensal are harmless. In all such cases the protozoa multiply in the region, such as a water supply, or the fluids of

. Foundations of Botany. Botany. EOOTS 39 it may readily be transferred to moderately damp soil, and that the whole plant presents curious modifications when made to grow in earth instead of water. 51. Parasitic Roots.1 — The dodder, the mistletoe, and a good many other parasites, live upon nourishment which they steal from other plants, called hosts. The parasitic. Fig. 15. — Aerial Adventitious Roots of the Ivy. roots, or haustoria, form the most intimate connections with the interior portions of the stem or the root, as the case may be, of the host-plant on which the parasite fastens itself Stock Photo

RMRHWKCA–. Foundations of Botany. Botany. EOOTS 39 it may readily be transferred to moderately damp soil, and that the whole plant presents curious modifications when made to grow in earth instead of water. 51. Parasitic Roots.1 — The dodder, the mistletoe, and a good many other parasites, live upon nourishment which they steal from other plants, called hosts. The parasitic. Fig. 15. — Aerial Adventitious Roots of the Ivy. roots, or haustoria, form the most intimate connections with the interior portions of the stem or the root, as the case may be, of the host-plant on which the parasite fastens itself

. A manual of zoology. Zoology. Fig. 139.—Leucozyto:iocm ziemanni (after Schaudinn). a-c, growth and multi- plication of nuclei in ookinete, in intestine of mosquito; d, transformation of ripe ookinete into Spirochsete; e, division of Leucozytozoon. accomplished by blood-sucking animals; insects (mosquitos, flies, lice, etc.) for mammals and fjirds; leeches (Piscicola) for fishes. Fertilization very probably takes place in the intermediate host. The following account, doubtful in several points, is given for Trypanosoma (Leucozytozoon) ziemanni. After the parasite has multiplied rapidly for so Stock Photo

RMRDHDEA–. A manual of zoology. Zoology. Fig. 139.—Leucozyto:iocm ziemanni (after Schaudinn). a-c, growth and multi- plication of nuclei in ookinete, in intestine of mosquito; d, transformation of ripe ookinete into Spirochsete; e, division of Leucozytozoon. accomplished by blood-sucking animals; insects (mosquitos, flies, lice, etc.) for mammals and fjirds; leeches (Piscicola) for fishes. Fertilization very probably takes place in the intermediate host. The following account, doubtful in several points, is given for Trypanosoma (Leucozytozoon) ziemanni. After the parasite has multiplied rapidly for so

. The Canadian entomologist. Insects; Entomology. 240 THE CANADIAN ENTOMOLOGIST.. and the nymphs in a pill-box, all on moist sand. On May 4th, when examined, the nymphs appeared unusually swollen, so that parasitism was suspected, and they were immediately isolated in small tubes with absorbent cotton stoppers. The posterior portion of the body of the host soon became translucent, indi- cating that parasite larvae were at that end of the body. The first adult parasites appeared May 22, and 51 specimens issued from five ticks on the 22nd and 23rd. The full life-history of the parasite is not kn Stock Photo

RMRG3145–. The Canadian entomologist. Insects; Entomology. 240 THE CANADIAN ENTOMOLOGIST.. and the nymphs in a pill-box, all on moist sand. On May 4th, when examined, the nymphs appeared unusually swollen, so that parasitism was suspected, and they were immediately isolated in small tubes with absorbent cotton stoppers. The posterior portion of the body of the host soon became translucent, indi- cating that parasite larvae were at that end of the body. The first adult parasites appeared May 22, and 51 specimens issued from five ticks on the 22nd and 23rd. The full life-history of the parasite is not kn

. Botany of the living plant. Botany; Plants. IRREGULAR NUTRITION 223 a sucker penetrates the living tissues of the host. In Viscum a suctorial system spreads from the original centre within the tissues of the host, penetrating along the region of the cambium. But in Loranthus the shoot of the parasite creeps along the outside of the host, and puts in suckers at intervals (Fig. 150). All these green parasites establish a relation with the conducting sys- tem of the host, especially with its xylem. Water with its dissolved. Fig. 150. Loranthus parasitic externally upon a branch of an Alligator Stock Photo

RMRH8WB3–. Botany of the living plant. Botany; Plants. IRREGULAR NUTRITION 223 a sucker penetrates the living tissues of the host. In Viscum a suctorial system spreads from the original centre within the tissues of the host, penetrating along the region of the cambium. But in Loranthus the shoot of the parasite creeps along the outside of the host, and puts in suckers at intervals (Fig. 150). All these green parasites establish a relation with the conducting sys- tem of the host, especially with its xylem. Water with its dissolved. Fig. 150. Loranthus parasitic externally upon a branch of an Alligator

. Bulletin - United States National Museum. Science. 322 BULLETIN 120, UNITED STATES NATIONAL MUSEUM, there was connection between Euro-Asia and extreme western United States, but the migration which brought to America the ancestors of Scaphiopus and its Protoopalinas quite likely occurred later, for.. neither host nor parasite are present in South America. The evolu- tion of Scaphiopus and of its Protoopalinas in North America was probably Tertiary or later (figs, 237, 238).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readabi Stock Photo

RMRG7WM7–. Bulletin - United States National Museum. Science. 322 BULLETIN 120, UNITED STATES NATIONAL MUSEUM, there was connection between Euro-Asia and extreme western United States, but the migration which brought to America the ancestors of Scaphiopus and its Protoopalinas quite likely occurred later, for.. neither host nor parasite are present in South America. The evolu- tion of Scaphiopus and of its Protoopalinas in North America was probably Tertiary or later (figs, 237, 238).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readabi

. Annual report. Entomological Society of Ontario; Insect pests; Insects. 74 THE REPORT OF THE Egg Parasitism Egg parasitism was not noted prior to 1928 and the only species re- covered this season was the cosmopolitan chalcid, Trichogramma minutum Riley. Ascogaster carpocapsae Viereck, which was present in small num- bers can scarcely be considered an egg parasite since its oviposition in the egg of the host does not prevent hatching and development of the par- asite takes place in the host larvae. The occurrence of Trichogramma was first brought to our attention on July 3 when an adult was n Stock Photo

RMRMABC8–. Annual report. Entomological Society of Ontario; Insect pests; Insects. 74 THE REPORT OF THE Egg Parasitism Egg parasitism was not noted prior to 1928 and the only species re- covered this season was the cosmopolitan chalcid, Trichogramma minutum Riley. Ascogaster carpocapsae Viereck, which was present in small num- bers can scarcely be considered an egg parasite since its oviposition in the egg of the host does not prevent hatching and development of the par- asite takes place in the host larvae. The occurrence of Trichogramma was first brought to our attention on July 3 when an adult was n

. Introduction to botany. Botany. Roots. 41. has no green leaves, as in the case of dodder (see Fig. 15), it must depend upon its host for all kinds of food mare- rials, — for the starches, sugars, oils, and proteids manufac- tured by its host. It is, in other words, a complete parasite. But if, as in the case of the mistletoe, it has green leaves of its own, it is entirely dependent on its host for the water and dis- solved soil materials only, and is then but partly parasitic. 31. Roots of Air Plants. — The aerial roots of some tropical orchids and of other aerial plants (see Fig. 16) do not Stock Photo

RMRDTRPH–. Introduction to botany. Botany. Roots. 41. has no green leaves, as in the case of dodder (see Fig. 15), it must depend upon its host for all kinds of food mare- rials, — for the starches, sugars, oils, and proteids manufac- tured by its host. It is, in other words, a complete parasite. But if, as in the case of the mistletoe, it has green leaves of its own, it is entirely dependent on its host for the water and dis- solved soil materials only, and is then but partly parasitic. 31. Roots of Air Plants. — The aerial roots of some tropical orchids and of other aerial plants (see Fig. 16) do not

. Pathogenic micro-organisms. A text-book of microbiology for physicians and students of medicine. (Based upon Williams' Bacteriology). Bacteriology; Pathogenic bacteria. 442 . SPECIFIC MICRO-ORGANISMS the salivary glands, from which they escape into the human host when the mosquito bites. The cycle in Anopheles requires eight days at a temperature of 28° to ^o" C. At temperatures below 17° C. the microgametes are not produced. Development of the estivo-autumnal parasite through the stages of schizogony has been obtained by Bass and Johns^ in the test-tube, in a medium consisting of defib Stock Photo

RMRE3Y2G–. Pathogenic micro-organisms. A text-book of microbiology for physicians and students of medicine. (Based upon Williams' Bacteriology). Bacteriology; Pathogenic bacteria. 442 . SPECIFIC MICRO-ORGANISMS the salivary glands, from which they escape into the human host when the mosquito bites. The cycle in Anopheles requires eight days at a temperature of 28° to ^o" C. At temperatures below 17° C. the microgametes are not produced. Development of the estivo-autumnal parasite through the stages of schizogony has been obtained by Bass and Johns^ in the test-tube, in a medium consisting of defib

. Introduction to botany. Botany. 240 INTRODUCTION TO BOTANY by the grape leaf, until the fungus permeates the entire leaf. If the leaf is not able to make a surplus of food material, the amount taken by the parasite may result in the starvation and death of the grape leaf. Possibly, also, the parasite may excrete substances that poison the host plant.. Fio. 187. Experiments in destroying potato blight Photograph by the New York Agricultural Experiment Station illustrating the results of spraying potatoes to prevent disease. Those that were not sprayed yielded at the rate of 161 bushels per ac Stock Photo

RMRE2JY8–. Introduction to botany. Botany. 240 INTRODUCTION TO BOTANY by the grape leaf, until the fungus permeates the entire leaf. If the leaf is not able to make a surplus of food material, the amount taken by the parasite may result in the starvation and death of the grape leaf. Possibly, also, the parasite may excrete substances that poison the host plant.. Fio. 187. Experiments in destroying potato blight Photograph by the New York Agricultural Experiment Station illustrating the results of spraying potatoes to prevent disease. Those that were not sprayed yielded at the rate of 161 bushels per ac

. Essentials of botany. Botany; Botany. Fig. 185. Armillaria mellea (often known as Agaricus melleus). This is a basidia fungus which can live either as a parasite or a saprophyte. As a parasite it is very destructive to the roots of coniferous trees. A, fructifications of various ages; c, c', very young " buttons "; st, the stem or stipe; r, the ring (the remains of a membrane by which the margin of ' the cap was at first attached to the stalk); g, the gills. B, branching myce- lium spread out between the bark and the wood of the root of the host. study, though the directions which Stock Photo

RMRDG50R–. Essentials of botany. Botany; Botany. Fig. 185. Armillaria mellea (often known as Agaricus melleus). This is a basidia fungus which can live either as a parasite or a saprophyte. As a parasite it is very destructive to the roots of coniferous trees. A, fructifications of various ages; c, c', very young " buttons "; st, the stem or stipe; r, the ring (the remains of a membrane by which the margin of ' the cap was at first attached to the stalk); g, the gills. B, branching myce- lium spread out between the bark and the wood of the root of the host. study, though the directions which

. The British rust fungi (Uredinales) their biology and classification. Rust fungi. ON THESIUM 229 ^cidia on Geranium pusillum, and possibly also on G. iriolle, G. rotundifolium; uredo- and teleutospores on Polygonum Con- volvulus, August and September. Uncommon. (Fig. 176.) The connection of the Eeoidium on the first-named host and the Puccinia on Pol. Convolvulus has been experimentally demonstrated by Tranzschel. It is possible that the same parasite also attacks P. dume- torum, P. Persioaria and others. The secidium is not known for certain to have occurred in Britain. The teleuto-sori of Stock Photo

RMRE379C–. The British rust fungi (Uredinales) their biology and classification. Rust fungi. ON THESIUM 229 ^cidia on Geranium pusillum, and possibly also on G. iriolle, G. rotundifolium; uredo- and teleutospores on Polygonum Con- volvulus, August and September. Uncommon. (Fig. 176.) The connection of the Eeoidium on the first-named host and the Puccinia on Pol. Convolvulus has been experimentally demonstrated by Tranzschel. It is possible that the same parasite also attacks P. dume- torum, P. Persioaria and others. The secidium is not known for certain to have occurred in Britain. The teleuto-sori of

. Bulletin. 1901-13. Agriculture; Agriculture. EFFECT UPON THE HOST. 19 killed by freezing, or otherwise being mechanically destroyed. It is maintained that in extreme cold weather mistletoe has been largely killed out over large areas; for example, in the unprecedented cold wave of February, 1900. Its own bulkiness and brittleness would seem to operate toward the self-destruction of the mistletoe bush. In the case of infection upon the mesquite, spoken of elsewhere, the parasite so injures the branch upon which it sits as to kill the branch and thereby destroy itself. Usually, however, accide Stock Photo

RMRGWK7B–. Bulletin. 1901-13. Agriculture; Agriculture. EFFECT UPON THE HOST. 19 killed by freezing, or otherwise being mechanically destroyed. It is maintained that in extreme cold weather mistletoe has been largely killed out over large areas; for example, in the unprecedented cold wave of February, 1900. Its own bulkiness and brittleness would seem to operate toward the self-destruction of the mistletoe bush. In the case of infection upon the mesquite, spoken of elsewhere, the parasite so injures the branch upon which it sits as to kill the branch and thereby destroy itself. Usually, however, accide

. Outlines of plant life : with special reference to form and function . Botany. SYMBIOSIS. 259 reckoned as semi-parasitic, having still green leaves and true roots. In addition, however, special organs are developed for attaching the parasite to the roots of other plants, from which at least a water supply and probably food materials are absorbed (fig. 217). Other semi-parasites, such as the mistletoe, attach themselves to the host above ground, and have no true roots of their own. Some parasitic seed plants twine about their hosts, and send into them absorbing organs by means of which they d Stock Photo

RMRDHNCD–. Outlines of plant life : with special reference to form and function . Botany. SYMBIOSIS. 259 reckoned as semi-parasitic, having still green leaves and true roots. In addition, however, special organs are developed for attaching the parasite to the roots of other plants, from which at least a water supply and probably food materials are absorbed (fig. 217). Other semi-parasites, such as the mistletoe, attach themselves to the host above ground, and have no true roots of their own. Some parasitic seed plants twine about their hosts, and send into them absorbing organs by means of which they d

. Plant studies; an elementary botany. Botany. THE NUTKITIoN OF I'LAXTS 161 oaks and tlu'ir allies, etc. (Figs. 140, 1.50). Tlie delicate branching filaments (hypha?) of the fungus spread through the soil, wrap the rootlets with a mesh of hyplux', and pene- trate into the cells. It seems clear that the fungus obtains food from the rootlet as a parasite; but it is also thought that the hyphal threads, spreading widely through the soil, are of great service to the host plant in aiding the rootlets in absorl)ing. If this be true, there is mutual ad- vantage in the association, for the small amoun Stock Photo

RMRDGWE7–. Plant studies; an elementary botany. Botany. THE NUTKITIoN OF I'LAXTS 161 oaks and tlu'ir allies, etc. (Figs. 140, 1.50). Tlie delicate branching filaments (hypha?) of the fungus spread through the soil, wrap the rootlets with a mesh of hyplux', and pene- trate into the cells. It seems clear that the fungus obtains food from the rootlet as a parasite; but it is also thought that the hyphal threads, spreading widely through the soil, are of great service to the host plant in aiding the rootlets in absorl)ing. If this be true, there is mutual ad- vantage in the association, for the small amoun

. Foundations of botany. Botany; Botany. BOOTS 39 it may readily be transferred to moderately damp soil, and that the whole plant presents curious modifications when made to grow in earth instead of water. 51. Parasitic Roots.' — The dodder, the mistletoe, and a good many other parasites, live upon nourishment which they steal from other plants, called hosts. The parasitic. Fig. 15. — Aerial Adyentitlous Roots of the Ivy. roots, or haustoria, form the most intimate connections with the interior portions of the stem or the root, as the case may be, of the host-plant on which the parasite fasten Stock Photo

RMRDHJ21–. Foundations of botany. Botany; Botany. BOOTS 39 it may readily be transferred to moderately damp soil, and that the whole plant presents curious modifications when made to grow in earth instead of water. 51. Parasitic Roots.' — The dodder, the mistletoe, and a good many other parasites, live upon nourishment which they steal from other plants, called hosts. The parasitic. Fig. 15. — Aerial Adyentitlous Roots of the Ivy. roots, or haustoria, form the most intimate connections with the interior portions of the stem or the root, as the case may be, of the host-plant on which the parasite fasten

. A biology of Crustacea. Crustacea. [20 A BIOLOGY OF CRUSTACEA they are enclosed in a membrane which is made by the crab. In the later stages of infection the cavity enclosed by the membrane communicates with the outside via a hole in the inner wall of the host's gill chamber. The usual epicardian larval stages are passed through, and the parasite enters the crab as a cryptoniscus. This moults and loses its limbs so that it resembles a small maggot. The blood cells of the host react to the presence of the parasite by gathering around it and enclosing it in a membrane, but the young parasite m Stock Photo

RMRHK8PC–. A biology of Crustacea. Crustacea. [20 A BIOLOGY OF CRUSTACEA they are enclosed in a membrane which is made by the crab. In the later stages of infection the cavity enclosed by the membrane communicates with the outside via a hole in the inner wall of the host's gill chamber. The usual epicardian larval stages are passed through, and the parasite enters the crab as a cryptoniscus. This moults and loses its limbs so that it resembles a small maggot. The blood cells of the host react to the presence of the parasite by gathering around it and enclosing it in a membrane, but the young parasite m

. The British rust fungi (Uredinales), their biology and classification. Uredineae. ON THESIUM 229 iEcidia on Geranium pusillum, and possibly also on G. molle, G. rotundifolium; uredo- and teleutospores on Polygonum Con- volvulus, August and September. Uncommon. (Fig. 17().) The connection of the jecidium on tlie tirst-named host and the Puccinia on Pol. Convolvulus has been experimentally demonstrated by Tranzschel. It is possible that the same parasite also attacks P. dume- torum, P. Persicaria and others. The secidium is not known for certain to have occurred in Britain. The teleuto-sori of Stock Photo

RMRH1H6A–. The British rust fungi (Uredinales), their biology and classification. Uredineae. ON THESIUM 229 iEcidia on Geranium pusillum, and possibly also on G. molle, G. rotundifolium; uredo- and teleutospores on Polygonum Con- volvulus, August and September. Uncommon. (Fig. 17().) The connection of the jecidium on tlie tirst-named host and the Puccinia on Pol. Convolvulus has been experimentally demonstrated by Tranzschel. It is possible that the same parasite also attacks P. dume- torum, P. Persicaria and others. The secidium is not known for certain to have occurred in Britain. The teleuto-sori of

. Animal parasites and parasitic diseases. Horses; Domestic animals -- Parasites; Veterinary medicine. PARASITOLOGY. 41 whose quarters are separated only by a partition, may get upon horses and cattle and cause temporary parasitism. Each parasite has its own host or hosts and will not live permanently upon another. Lice of Birds. The Large Hen Louse.—Menopon Biseriatum. This is the largest louse found upon the hen. It is about one-twelfth of an inch in length, light in color, with mouth parts arranged for mastication as illustrated in Fig. 10. The free extremities of the legs are provided with Stock Photo

RMRN53CY–. Animal parasites and parasitic diseases. Horses; Domestic animals -- Parasites; Veterinary medicine. PARASITOLOGY. 41 whose quarters are separated only by a partition, may get upon horses and cattle and cause temporary parasitism. Each parasite has its own host or hosts and will not live permanently upon another. Lice of Birds. The Large Hen Louse.—Menopon Biseriatum. This is the largest louse found upon the hen. It is about one-twelfth of an inch in length, light in color, with mouth parts arranged for mastication as illustrated in Fig. 10. The free extremities of the legs are provided with

. Diseases of greenhouse crops and their control . Vegetables; Plant diseases; Plant diseases. Fig. 68. Rubber Plant and Schizanthus Diseases. a. Leptostromella leaf spot, b. cross section of rubber leaf to show relationship of the parasite to its host, to the left one magnified spore (after Hatch Expt. Sta. 9th Rept. 1897), c.^ and d. acervulus and germinating spores of Colletrotrichum schisanthi Ten (after Jensen, C. N.).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustratio Stock Photo

RMRDBF9M–. Diseases of greenhouse crops and their control . Vegetables; Plant diseases; Plant diseases. Fig. 68. Rubber Plant and Schizanthus Diseases. a. Leptostromella leaf spot, b. cross section of rubber leaf to show relationship of the parasite to its host, to the left one magnified spore (after Hatch Expt. Sta. 9th Rept. 1897), c.^ and d. acervulus and germinating spores of Colletrotrichum schisanthi Ten (after Jensen, C. N.).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustratio

. The animals and man; an elementary textbook of zoology and human physiology. Zoology; Physiology. 412 THE ANIMALS AND MAN like sac fastened to the crab by means of the feeding root- lets. Loss by degeneration of the body-parts is carried very far in this case. Numerous other parasites live, like Sacculina, attached firmly to their host, and do not move about. They are. Fig. 205. Sacculina, a parasitic crustacean; A, attached to a crab, the root-like processes of the parasite penetrating the body of the host; B, the active larval condition; C, the adult removed from its host. (Enlarged; after Stock Photo

RMRDT33E–. The animals and man; an elementary textbook of zoology and human physiology. Zoology; Physiology. 412 THE ANIMALS AND MAN like sac fastened to the crab by means of the feeding root- lets. Loss by degeneration of the body-parts is carried very far in this case. Numerous other parasites live, like Sacculina, attached firmly to their host, and do not move about. They are. Fig. 205. Sacculina, a parasitic crustacean; A, attached to a crab, the root-like processes of the parasite penetrating the body of the host; B, the active larval condition; C, the adult removed from its host. (Enlarged; after

. Bulletin of the U.S. Department of Agriculture. Agriculture; Agriculture. 30 DEPARTME:CirT BULLETIN- 779. Telenomus ashmeadi in the natural control of C. sayi. Frequently death does not occur until several hours, or even days, after the parasite has left the body of its host, the host meanwhile remaining inactive. Although eggs are deposited on the nymphs, no instances were ob- served in which the larvae of G. fuliginosa completed their develop- ment and issued before the host reached its adult stage. The seasonal history of G. fuliginosa corresponds very closely with that of C. sayi and the Stock Photo

RMRGBRTM–. Bulletin of the U.S. Department of Agriculture. Agriculture; Agriculture. 30 DEPARTME:CirT BULLETIN- 779. Telenomus ashmeadi in the natural control of C. sayi. Frequently death does not occur until several hours, or even days, after the parasite has left the body of its host, the host meanwhile remaining inactive. Although eggs are deposited on the nymphs, no instances were ob- served in which the larvae of G. fuliginosa completed their develop- ment and issued before the host reached its adult stage. The seasonal history of G. fuliginosa corresponds very closely with that of C. sayi and the

. Bulletin. Agriculture -- New Hampshire. R Detmers, del. Fig. 4. Life stages of a Pimpla Parasite. (By the courtesy of the Ohio Exper- iment Station.) the stems of the evening primrose^ in which case the parasitic grub feeds externally on its host as shown at e. The most abundant species of Pimpla^''- however, as a parasite of the tent caterpillar lives inside the host, which generally is not killed until after it has spun its cocoon. In addition to the very general attack of the common tent caterpillar, there have been in many parts of the state more dangerous outbreaks of the Forest Tent Ca Stock Photo

RMRH13GD–. Bulletin. Agriculture -- New Hampshire. R Detmers, del. Fig. 4. Life stages of a Pimpla Parasite. (By the courtesy of the Ohio Exper- iment Station.) the stems of the evening primrose^ in which case the parasitic grub feeds externally on its host as shown at e. The most abundant species of Pimpla^''- however, as a parasite of the tent caterpillar lives inside the host, which generally is not killed until after it has spun its cocoon. In addition to the very general attack of the common tent caterpillar, there have been in many parts of the state more dangerous outbreaks of the Forest Tent Ca

. Common diseases of farm animals. Veterinary medicine. 320 INFECTIOUS DISEASES Vaccination of the exposed or susceptible animals should be practised. On farms where the disease exists it may be neces- sary to vaccinate the young animals (less than two years of age) once or twice every year in order to prevent the disease. Medic- inal treatment is unsatisfactory. Texas or Tick Fever.—Tick fever is an infectious disease of cattle. It is caused by an animal organism that is present in the blood, and is conveyed from the animal that is host for the tick fever parasite to the non-infected animal b Stock Photo

RMREFKHA–. Common diseases of farm animals. Veterinary medicine. 320 INFECTIOUS DISEASES Vaccination of the exposed or susceptible animals should be practised. On farms where the disease exists it may be neces- sary to vaccinate the young animals (less than two years of age) once or twice every year in order to prevent the disease. Medic- inal treatment is unsatisfactory. Texas or Tick Fever.—Tick fever is an infectious disease of cattle. It is caused by an animal organism that is present in the blood, and is conveyed from the animal that is host for the tick fever parasite to the non-infected animal b

. Botany; an elementary text for schools. Plants. 184 STUDIES IN CRYPTOGAMS. 325. ori containing teleu- tospores of wheat true parasite, affecting wheat and a few other grasses. The mycelium here cannot be seen by the unaided eye, for it consists of threads which are present within the host plant, mostly in the intercellular spaces. These threads also send short branches, or haustoria (180), into the neighboring cells to absorb nutriment. The resting-spores of wheat rust are produced in late summer, when they may be found in black lines breaking through the epidermis of the wheat-stalk. They a Stock Photo

RMRH8YXR–. Botany; an elementary text for schools. Plants. 184 STUDIES IN CRYPTOGAMS. 325. ori containing teleu- tospores of wheat true parasite, affecting wheat and a few other grasses. The mycelium here cannot be seen by the unaided eye, for it consists of threads which are present within the host plant, mostly in the intercellular spaces. These threads also send short branches, or haustoria (180), into the neighboring cells to absorb nutriment. The resting-spores of wheat rust are produced in late summer, when they may be found in black lines breaking through the epidermis of the wheat-stalk. They a

. Annual report of the Commissioner of Agriculture ... Agriculture -- New York (State). Diseases of Alfalfa and Clover -VJ DODDER The dodders, Cuscuta sp., are parasitic flowering plants which attack a great niunber of hosts. In clover and alfalfa fields, dodder may become very destructive, killing in ever-widening circles. In the center of the infested areas the host plants will be entirely killed, while about the margin of these dead areas will be seen the dense mat of orange or yellowish stems. The parasite consists of slender, yellowish or orange-colored, much-branched stems, on which are Stock Photo

RMRM8GCT–. Annual report of the Commissioner of Agriculture ... Agriculture -- New York (State). Diseases of Alfalfa and Clover -VJ DODDER The dodders, Cuscuta sp., are parasitic flowering plants which attack a great niunber of hosts. In clover and alfalfa fields, dodder may become very destructive, killing in ever-widening circles. In the center of the infested areas the host plants will be entirely killed, while about the margin of these dead areas will be seen the dense mat of orange or yellowish stems. The parasite consists of slender, yellowish or orange-colored, much-branched stems, on which are

. The biology of marine animals. Marine animals; Physiology, Comparative. EFFECTOR MECHANISMS 373 filament which in some species reaches a length fifty times that of the spore (Fig. 9.2). Exposure to the digestive fluids of the host causes the contained thread to unroll and shoot out. The discharged threads serve temporarily to anchor the parasite to the gut wall of the host (27, 30, 49, 56, 59, 101). Nematocysts and Colloblasts Nematocysts or stinging cells are found in coelenterates. Colloblasts or adhesive cells occur in ctenophores. The nematocysts of coelenterates are small capsules lying Stock Photo

RMRHK2PH–. The biology of marine animals. Marine animals; Physiology, Comparative. EFFECTOR MECHANISMS 373 filament which in some species reaches a length fifty times that of the spore (Fig. 9.2). Exposure to the digestive fluids of the host causes the contained thread to unroll and shoot out. The discharged threads serve temporarily to anchor the parasite to the gut wall of the host (27, 30, 49, 56, 59, 101). Nematocysts and Colloblasts Nematocysts or stinging cells are found in coelenterates. Colloblasts or adhesive cells occur in ctenophores. The nematocysts of coelenterates are small capsules lying

. An introduction to zoology, with directions for practical work (invertebrates). . „ „„ „ . , , Fig. 328.—Caterpillar of Pieris Fig. 327. -Panwus testaceus. brassicae Infested witli Apan- A common Ichneumon Wasp. teles glomeratus (Braconidae). Cabbage White Butterfly, laying a great number of eggs in its body. The larvae of the parasite develop within, absorbing the juices of their host without at first apparently incommoding it, for it eats voraciously all the time and appears healthy. Finally, however, the larvae emerge through its skin in order to pupate, and the caterpillar usually now d Stock Photo

RMRDHJK5–. An introduction to zoology, with directions for practical work (invertebrates). . „ „„ „ . , , Fig. 328.—Caterpillar of Pieris Fig. 327. -Panwus testaceus. brassicae Infested witli Apan- A common Ichneumon Wasp. teles glomeratus (Braconidae). Cabbage White Butterfly, laying a great number of eggs in its body. The larvae of the parasite develop within, absorbing the juices of their host without at first apparently incommoding it, for it eats voraciously all the time and appears healthy. Finally, however, the larvae emerge through its skin in order to pupate, and the caterpillar usually now d

. North American trees : being descriptions and illustrations of the trees growing independently of cultivation in North America, north of Mexico and the West Indies . Trees. Golden Fig 369. Fig. 327. — Golden Fig. I. GOLDEN FIG—Ficus aurea NuttaU This tree starts into life as a parasite; the seed germinating in the crevices of the bark of other trees, produces aerial roots which, when they reach the ground, take root and become trunks; often several of these descend parallel, and sur- rounding the trunk of their host, finally come together and strangle, it. The branches also send down roots, Stock Photo

RMRDBGE4–. North American trees : being descriptions and illustrations of the trees growing independently of cultivation in North America, north of Mexico and the West Indies . Trees. Golden Fig 369. Fig. 327. — Golden Fig. I. GOLDEN FIG—Ficus aurea NuttaU This tree starts into life as a parasite; the seed germinating in the crevices of the bark of other trees, produces aerial roots which, when they reach the ground, take root and become trunks; often several of these descend parallel, and sur- rounding the trunk of their host, finally come together and strangle, it. The branches also send down roots,

. Fundamentals of botany. Botany. SAPROPHYTISM AND SYMBIOSIS 341 semi-parasitism is that of the blue-green alga, Nostoc, species of which grow in little pockets or cavities in the tissues of the water-fern Salvinia, of Gunnera manicata,. Fig. 249.—Photomicrograph of a cross-section of the stem of a (ficoty- ledonous host-plant infested with the parasite, dodder {Cuscuta Sp.). Note the haustoria extending from the dodder (D, D') into the cortex of the host (H). Greatly enlarged. of Anthoceros, and of other plants, without apparent injury to the host (Fig. 160). 312. Artificial Parasites.—By rec Stock Photo

RMRE2FD9–. Fundamentals of botany. Botany. SAPROPHYTISM AND SYMBIOSIS 341 semi-parasitism is that of the blue-green alga, Nostoc, species of which grow in little pockets or cavities in the tissues of the water-fern Salvinia, of Gunnera manicata,. Fig. 249.—Photomicrograph of a cross-section of the stem of a (ficoty- ledonous host-plant infested with the parasite, dodder {Cuscuta Sp.). Note the haustoria extending from the dodder (D, D') into the cortex of the host (H). Greatly enlarged. of Anthoceros, and of other plants, without apparent injury to the host (Fig. 160). 312. Artificial Parasites.—By rec

. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. VINEYARD CONDITIONS IN LAKE ERIE VALLEY. 57 emerged. The host had been confined indoors during the winter, thus bringing out the hymenopterous parasite on February 2. It is probable that the root-worm eggs were first parasitized by the dip- terous insect and that later the eggs along the margin of the cluster were parasitized a second time by Lath- romeris fidix. The dipterous and the hymenopterous insects are undoubtedly both primary parasites.^. VINEYARD CONDITIONS IN THE LAKE ERIE VALLEY. Fig. 27.—Lathromeris Stock Photo

RMRGWM63–. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. VINEYARD CONDITIONS IN LAKE ERIE VALLEY. 57 emerged. The host had been confined indoors during the winter, thus bringing out the hymenopterous parasite on February 2. It is probable that the root-worm eggs were first parasitized by the dip- terous insect and that later the eggs along the margin of the cluster were parasitized a second time by Lath- romeris fidix. The dipterous and the hymenopterous insects are undoubtedly both primary parasites.^. VINEYARD CONDITIONS IN THE LAKE ERIE VALLEY. Fig. 27.—Lathromeris

. An introduction to vegetable physiology. Plant physiology. 388 -VEGETABLE PHYSIOLOGY. wall or other support to which it is clinging. The roots of Thesium show a similar property. When they come into contact with other roots growing near them they develop a swelling at the point 13 of contact, from which certain cells grow out and penetrate the host, forming haust- oria (fig. 157). The parasite Guscuta, often found growing on clover, is affected in the same way, first twining round the clover stem and then putting out haustoria, which penetrate its tissues (fig. 158). Another form of irritabi Stock Photo

RMRDYH4T–. An introduction to vegetable physiology. Plant physiology. 388 -VEGETABLE PHYSIOLOGY. wall or other support to which it is clinging. The roots of Thesium show a similar property. When they come into contact with other roots growing near them they develop a swelling at the point 13 of contact, from which certain cells grow out and penetrate the host, forming haust- oria (fig. 157). The parasite Guscuta, often found growing on clover, is affected in the same way, first twining round the clover stem and then putting out haustoria, which penetrate its tissues (fig. 158). Another form of irritabi

. Common diseases of farm animals. Veterinary medicine. 320 INFECTIOUS DISEASES Vaccinatio7i of the exposed or susceptible animals should be practised. On farms where the disease exists it may be neces- sary to vaccinate the young animals (less than two years of age) once or twice every year in order to prevent the disease. Medic- inal treatment is unsatisfactory. Texas or Tick Fever.—Tick fever is an infectious disease of cattle. It is caused by an animal organism that is present in the blood, and is conveyed from the animal that is host for the tick fever parasite to the non-infected animal Stock Photo

RMREFKBM–. Common diseases of farm animals. Veterinary medicine. 320 INFECTIOUS DISEASES Vaccinatio7i of the exposed or susceptible animals should be practised. On farms where the disease exists it may be neces- sary to vaccinate the young animals (less than two years of age) once or twice every year in order to prevent the disease. Medic- inal treatment is unsatisfactory. Texas or Tick Fever.—Tick fever is an infectious disease of cattle. It is caused by an animal organism that is present in the blood, and is conveyed from the animal that is host for the tick fever parasite to the non-infected animal

. Animal parasites and parasitic diseases . Domestic animals; Veterinary medicine. PARASITOLOGV. 41 whose quarters are separated only by a partition, may get upon horses and cattle and cause temporary parasitism. Each parasite has its own host or hosts and will not live permanently upon another. Lice of Birds. The Large Hen Louse.—Menopon Biseriatum. This is the largest louse found upon the hen. It is about one-twelfth of an inch in length, light in color, with mouth parts arranged for mastication as illustrated in Fig. 10. The free extremities of the legs are provided with booklets which aid Stock Photo

RMRDGPBH–. Animal parasites and parasitic diseases . Domestic animals; Veterinary medicine. PARASITOLOGV. 41 whose quarters are separated only by a partition, may get upon horses and cattle and cause temporary parasitism. Each parasite has its own host or hosts and will not live permanently upon another. Lice of Birds. The Large Hen Louse.—Menopon Biseriatum. This is the largest louse found upon the hen. It is about one-twelfth of an inch in length, light in color, with mouth parts arranged for mastication as illustrated in Fig. 10. The free extremities of the legs are provided with booklets which aid

. A manual for the study of insects. Insects. 590 THE STUDY OF INSECTS, of attack of these parasites is between two abdominal segments of the host. The presence of one of these para- sites is indicated by an irregularity in the outline of the abdomen of the infested wasp or bee; and, too, the heads of the pupa cases of the parasites can be seen project- ing from the suture. ** The head of the pupa case of the male is convex, that of the female is flat; specimens con- taining male pupae can be kept confined with proper food until the parasite is hatched." (Le Conte and Horn.) Two genera oc Stock Photo

RMRD6YWX–. A manual for the study of insects. Insects. 590 THE STUDY OF INSECTS, of attack of these parasites is between two abdominal segments of the host. The presence of one of these para- sites is indicated by an irregularity in the outline of the abdomen of the infested wasp or bee; and, too, the heads of the pupa cases of the parasites can be seen project- ing from the suture. ** The head of the pupa case of the male is convex, that of the female is flat; specimens con- taining male pupae can be kept confined with proper food until the parasite is hatched." (Le Conte and Horn.) Two genera oc

. Genetics in relation to agriculture. Livestock; Heredity; Variation (Biology); Plant breeding. 406 GENETICS IN RELATION TO AGRICULTURE parasitica. The parasite is a native of eastern Asia where it is parasitic upon native species of chestnut, to which it appears to do relatively Uttle harm. In other words these species are highly resistant to the parasite. However, when the fungus was introduced into America, pre- sumably in nursery stock some 25 years ago, it found in our native species, Castanea americana, a very susceptible host (Fig. 16.5). The parasite has already caused the destruction Stock Photo

RMRDYW0W–. Genetics in relation to agriculture. Livestock; Heredity; Variation (Biology); Plant breeding. 406 GENETICS IN RELATION TO AGRICULTURE parasitica. The parasite is a native of eastern Asia where it is parasitic upon native species of chestnut, to which it appears to do relatively Uttle harm. In other words these species are highly resistant to the parasite. However, when the fungus was introduced into America, pre- sumably in nursery stock some 25 years ago, it found in our native species, Castanea americana, a very susceptible host (Fig. 16.5). The parasite has already caused the destruction

. Botany of the living plant. Botany; Plants. 226 BOTANY OF THE LIVING PLANT. Fig. 153. Median section of a young plant of Orobanche seated upon the root of its host. (After Hovelacque.) ( x 20.) and cortex, thus tapping both storage and conducting tissues. Where the sucker impinges upon a vascular strand a continuous xylem- connection may be established ; in the phloem also a close relation of the sieve- tubes of the parasite with those of the host has been shown. The Broomrape (Orobanche), and the Toothwort (Lathraea) are further examples of parasites with complete physiologi- cal dependence Stock Photo

RMRH8W9H–. Botany of the living plant. Botany; Plants. 226 BOTANY OF THE LIVING PLANT. Fig. 153. Median section of a young plant of Orobanche seated upon the root of its host. (After Hovelacque.) ( x 20.) and cortex, thus tapping both storage and conducting tissues. Where the sucker impinges upon a vascular strand a continuous xylem- connection may be established ; in the phloem also a close relation of the sieve- tubes of the parasite with those of the host has been shown. The Broomrape (Orobanche), and the Toothwort (Lathraea) are further examples of parasites with complete physiologi- cal dependence

. The biology of flowering plants. Phanerogams; Plant physiology; Plant ecology; Plant Physiology. OTHER LORANTHACE.E 227 which suckers penetrate shoots of the host or even other branches of the parasite itself. On reaching the wood these suckers splay out to form an absorbing disc in contact with the wood, and this in its turn sends absorptive filaments into the medullary rays. Finally, some twining species of Struthanthus produce suckers directly from the stem. The securing of the seed to the host by a viscid layer of the fruit wall is universal in the family. Keeble (1895) states that the f Stock Photo

RMRHK822–. The biology of flowering plants. Phanerogams; Plant physiology; Plant ecology; Plant Physiology. OTHER LORANTHACE.E 227 which suckers penetrate shoots of the host or even other branches of the parasite itself. On reaching the wood these suckers splay out to form an absorbing disc in contact with the wood, and this in its turn sends absorptive filaments into the medullary rays. Finally, some twining species of Struthanthus produce suckers directly from the stem. The securing of the seed to the host by a viscid layer of the fruit wall is universal in the family. Keeble (1895) states that the f

. Plants; a text-book of botany. Botany. THE FOOD OF PLANTS 89 oaks and their allies, etc. (Figs. 76, 77). The delicate branching filaments (hyphse) of the fungus spread through the soil, wrap the rootlets with a mesh of hyphse, and pene- trate into the cells. It seems clear that the fungus obtains food from the rootlet as a parasite; but it is also thought that the hyphal threads, spreading widely through the soil, are of great service to the host plant in aiding the rootlets in absorbing. If this be true, there is mutual ad- vantage in the association, for the small amount of nourishment tak Stock Photo

RMRDTWE7–. Plants; a text-book of botany. Botany. THE FOOD OF PLANTS 89 oaks and their allies, etc. (Figs. 76, 77). The delicate branching filaments (hyphse) of the fungus spread through the soil, wrap the rootlets with a mesh of hyphse, and pene- trate into the cells. It seems clear that the fungus obtains food from the rootlet as a parasite; but it is also thought that the hyphal threads, spreading widely through the soil, are of great service to the host plant in aiding the rootlets in absorbing. If this be true, there is mutual ad- vantage in the association, for the small amount of nourishment tak

. British fungi. Fungi -- Great Britain; Botany -- Great Britain; Lichens. LICHENS 519 fungi attacking higher plants, can be observed at the present day. Incipient parasites often promptly kill their host-plant ; whereas, at the other extreme, many parasites do not kill the host-plant, neither, so far as our knowledge goes, do they cause the slightest inconvenience, and in some instances the presence of the parasite actually appears to benefit the host-plant. When parasite and host have reached the point, through a long series of struggles against each other, of mutually aiding each other, and Stock Photo

RMRH33K2–. British fungi. Fungi -- Great Britain; Botany -- Great Britain; Lichens. LICHENS 519 fungi attacking higher plants, can be observed at the present day. Incipient parasites often promptly kill their host-plant ; whereas, at the other extreme, many parasites do not kill the host-plant, neither, so far as our knowledge goes, do they cause the slightest inconvenience, and in some instances the presence of the parasite actually appears to benefit the host-plant. When parasite and host have reached the point, through a long series of struggles against each other, of mutually aiding each other, and

. The British rust fungi (Uredinales) their biology and classification. Rust fungi -- Great Britain. ON THESIUM 229 /Ecidia on Geranium pusillum, and possibly also on G. molle, G. rot a ml! folium; uredo- and teleutospores on Polygonum Con- volvulus, August and September. Uncommon. (Fig. 176.) The connection of the secidium on the first-named host and the Puccinia on Pol. Convolvulus has been experimentally demonstrated by Tranzschel. It is possible that the same parasite also attacks P. dume- toruin, P. Persicaria and others. The recidium is not known for certain to have occurred in Britain. Stock Photo

RMRH1H77–. The British rust fungi (Uredinales) their biology and classification. Rust fungi -- Great Britain. ON THESIUM 229 /Ecidia on Geranium pusillum, and possibly also on G. molle, G. rot a ml! folium; uredo- and teleutospores on Polygonum Con- volvulus, August and September. Uncommon. (Fig. 176.) The connection of the secidium on the first-named host and the Puccinia on Pol. Convolvulus has been experimentally demonstrated by Tranzschel. It is possible that the same parasite also attacks P. dume- toruin, P. Persicaria and others. The recidium is not known for certain to have occurred in Britain.

. Cassell's natural history. Animals; Animal behavior. THE ICUXEUMOXS. coutouts of its body. In some cases the lelmeiimon larva makes its way witliiu tli(> body of its host, uiul becomes an internal parasite ; in others it remains permanently on the outside, its hinder extremity being always enclosed between the valves of the egg-shell, and then, its body being very translucent, the transfer of the substance of the host to the parasite may be observed going on very actively. In the genus Emiiia and its allies we find ji very curious arrangement. The abdomen, instead of springing from the ba Stock Photo

RMRFPAJB–. Cassell's natural history. Animals; Animal behavior. THE ICUXEUMOXS. coutouts of its body. In some cases the lelmeiimon larva makes its way witliiu tli(> body of its host, uiul becomes an internal parasite ; in others it remains permanently on the outside, its hinder extremity being always enclosed between the valves of the egg-shell, and then, its body being very translucent, the transfer of the substance of the host to the parasite may be observed going on very actively. In the genus Emiiia and its allies we find ji very curious arrangement. The abdomen, instead of springing from the ba

. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); InvertÃ©brÃ©s; Morphologie (Animaux). mo INVEHTKBUA TE MOIWIIOLOG Y. 1 . yet beeu observed, but there is uo reason for doubtiug that it is the result of the partheiio^euetic developmeut of owe of the germ-cells which occur iu the body-cavity of the embryo. So loug, however, as it reiuaius iu the tissues of the Mollusk it undergoes no further development; it can only reach ma- turity in a second host, iu this case some water-bird which swallows the Mollusk and its eucapsuled parasite, when the latter, its Stock Photo

RMRJ4P54–. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); InvertÃ©brÃ©s; Morphologie (Animaux). mo INVEHTKBUA TE MOIWIIOLOG Y. 1 . yet beeu observed, but there is uo reason for doubtiug that it is the result of the partheiio^euetic developmeut of owe of the germ-cells which occur iu the body-cavity of the embryo. So loug, however, as it reiuaius iu the tissues of the Mollusk it undergoes no further development; it can only reach ma- turity in a second host, iu this case some water-bird which swallows the Mollusk and its eucapsuled parasite, when the latter, its

. Minnesota plant diseases. Plant diseases. Minnesota Plant Diseases. 59 the rest of the plant. Then arise the carbuncle-like swellings of the leaves. If a kernel of the cob is attacked it increases perhaps tenfold in size. During this increase of size the fungus is also gaining strength and keeping pace with its partner plant-part, and when the proper moment has arrived for the formation of its spores it proceeds rapidly and utilizes all the extra food stored up by the swollen host plant-parts and de- stroys the latter rapidly. Such a parasite stimulates its host to unusual activity for a lon Stock Photo

RMRDE4NM–. Minnesota plant diseases. Plant diseases. Minnesota Plant Diseases. 59 the rest of the plant. Then arise the carbuncle-like swellings of the leaves. If a kernel of the cob is attacked it increases perhaps tenfold in size. During this increase of size the fungus is also gaining strength and keeping pace with its partner plant-part, and when the proper moment has arrived for the formation of its spores it proceeds rapidly and utilizes all the extra food stored up by the swollen host plant-parts and de- stroys the latter rapidly. Such a parasite stimulates its host to unusual activity for a lon

. British fungi. Fungi -- Great Britain; Botany -- Great Britain; Lichens. DISEASES CAUSED BY FUNGI 55 during the winter on tlie dead, fallen leaves, and the fungus thus continues its annual cycle of development. In this instance the course of the fungus can be arrested by clearing away and burning all fallen infected leaves before the spores are liberated and dispersed by wind, animals, insects, etc., in the spring. Going to the other extreme, where the parasite has evolved the method of living along with its host-plant witliout causing injury, but, on the other hand, actually enabling the ho Stock Photo

RMRH1MHE–. British fungi. Fungi -- Great Britain; Botany -- Great Britain; Lichens. DISEASES CAUSED BY FUNGI 55 during the winter on tlie dead, fallen leaves, and the fungus thus continues its annual cycle of development. In this instance the course of the fungus can be arrested by clearing away and burning all fallen infected leaves before the spores are liberated and dispersed by wind, animals, insects, etc., in the spring. Going to the other extreme, where the parasite has evolved the method of living along with its host-plant witliout causing injury, but, on the other hand, actually enabling the ho

. Botany for academies and colleges: consisting of plant development and structure from seaweed to clematis. Botany; 1889. MONOPETAL^. 59 in diameter), and the rootlets it sends down into the host on which it lives; for the Kafflesia is a parasite. It is usually found on the sur- face-roots of a species of Cissus. The flower has a 5-parted perianth with numerous bracts below it; in the centre is a deep cup, or corona, which will hold 12 pints of water. The flowers are dioecious; their smell, like that of tainted beef, attracts flies, which aid in the work of fertilization. The Aristolochia (Pi Stock Photo

RMRDHCHK–. Botany for academies and colleges: consisting of plant development and structure from seaweed to clematis. Botany; 1889. MONOPETAL^. 59 in diameter), and the rootlets it sends down into the host on which it lives; for the Kafflesia is a parasite. It is usually found on the sur- face-roots of a species of Cissus. The flower has a 5-parted perianth with numerous bracts below it; in the centre is a deep cup, or corona, which will hold 12 pints of water. The flowers are dioecious; their smell, like that of tainted beef, attracts flies, which aid in the work of fertilization. The Aristolochia (Pi

. Animal parasites and human disease. Insect Vectors; Parasites; Parasitic Diseases; Medical parasitology; Insects as carriers of disease. DWARF TAPEWORM 243 by the armed head, and become adult. It is said that eggs of this parasite can be found in the faeces within a month after an egg of the preceding generation has been swallowed. Self- infection with these eggs rarely occurs, since the eggs will not develop unless acted upon by the gastric juices. There is still room for doubt as to whether an insect is not commonly involved as an intermediate host as in other species of Hymenolepis; in fa Stock Photo

RMRN524P–. Animal parasites and human disease. Insect Vectors; Parasites; Parasitic Diseases; Medical parasitology; Insects as carriers of disease. DWARF TAPEWORM 243 by the armed head, and become adult. It is said that eggs of this parasite can be found in the faeces within a month after an egg of the preceding generation has been swallowed. Self- infection with these eggs rarely occurs, since the eggs will not develop unless acted upon by the gastric juices. There is still room for doubt as to whether an insect is not commonly involved as an intermediate host as in other species of Hymenolepis; in fa

. Practical botany. Botany. 230 PEACTICAL BOTANY found upon the willow, oak, some of the smartweeds, and- upon many other plants. The powdery mycelium lives upon the surfaces of the leaves. Haustoria, by means of which nutrient material is extracted from the host, are sent into the leaf from the superficial hyphae. The fungus is therefore a superficial parasite. At times upright hyphse form transverse walls, cutting from their tips rows of small cells, the conidia. The powdery appearance of the mildews S^J^^ is due largely to the pres- ence of large numbers of these conidia. The co- nidia, if Stock Photo

RMRE3B2T–. Practical botany. Botany. 230 PEACTICAL BOTANY found upon the willow, oak, some of the smartweeds, and- upon many other plants. The powdery mycelium lives upon the surfaces of the leaves. Haustoria, by means of which nutrient material is extracted from the host, are sent into the leaf from the superficial hyphae. The fungus is therefore a superficial parasite. At times upright hyphse form transverse walls, cutting from their tips rows of small cells, the conidia. The powdery appearance of the mildews S^J^^ is due largely to the pres- ence of large numbers of these conidia. The co- nidia, if

. Bulletin. 1901-13. Agriculture; Agriculture. 18 THE MISTLETOE PEST IN THE SOUTHWEST. spread of nearly 3 feet and to be more than an inch in diameter just above the buttressed point of attacliment to the slender branch of the host (PL II, fig. 1). The rate of growth varies with the host, being much slower in the cases of the mesquite and the osage orange. The location of the host with respect to moist or dry soils naturally also affects the rate of growth of the parasite. LONGEVITY. The parts of mistletoe embedded in the tissues of its host appear to have no fixed limit to continued existence Stock Photo

RMRGWK81–. Bulletin. 1901-13. Agriculture; Agriculture. 18 THE MISTLETOE PEST IN THE SOUTHWEST. spread of nearly 3 feet and to be more than an inch in diameter just above the buttressed point of attacliment to the slender branch of the host (PL II, fig. 1). The rate of growth varies with the host, being much slower in the cases of the mesquite and the osage orange. The location of the host with respect to moist or dry soils naturally also affects the rate of growth of the parasite. LONGEVITY. The parts of mistletoe embedded in the tissues of its host appear to have no fixed limit to continued existence

. Bulletin of the U.S. Department of Agriculture. Agriculture. a * c * ^b Fig. 17.—Dibrachys houcheanus: a, Larva; 6, pupa; c, adult female; d, heul of larva; e, antenna of ' male, highly magnified. Greatly enlarged. (After Howard.) johannseni and Chelonus slioshoneanorum, the former seeming to be its favorite host. Tliis species was reared from the egg in the laboratory, where it attacked the mature larvae of its hosts after they had spun their cocoons. Wliere the cocoons were not too thick to prevent it from reaching its host tiie parasite would often feed at the wounds caused by its oviposi Stock Photo

RMRGBJ38–. Bulletin of the U.S. Department of Agriculture. Agriculture. a * c * ^b Fig. 17.—Dibrachys houcheanus: a, Larva; 6, pupa; c, adult female; d, heul of larva; e, antenna of ' male, highly magnified. Greatly enlarged. (After Howard.) johannseni and Chelonus slioshoneanorum, the former seeming to be its favorite host. Tliis species was reared from the egg in the laboratory, where it attacked the mature larvae of its hosts after they had spun their cocoons. Wliere the cocoons were not too thick to prevent it from reaching its host tiie parasite would often feed at the wounds caused by its oviposi

. Bulletin of the U.S. Department of Agriculture. Agriculture; Agriculture. The Black-Walnut Curculio. a, Egg in natural position exposed by removing skin of young black walnut; 6, group of egg punctures in half-grown black'walnut; c, parasitic fly Cholomyia lonc/ipes; d, pupae within pupal cells in earth; e, cocoons of the parasite Thehilochus conotracheli occupying the pupal cells of the curculio after killing and devouring the host larvae. All enlarged.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration an Stock Photo

RMRGBEEM–. Bulletin of the U.S. Department of Agriculture. Agriculture; Agriculture. The Black-Walnut Curculio. a, Egg in natural position exposed by removing skin of young black walnut; 6, group of egg punctures in half-grown black'walnut; c, parasitic fly Cholomyia lonc/ipes; d, pupae within pupal cells in earth; e, cocoons of the parasite Thehilochus conotracheli occupying the pupal cells of the curculio after killing and devouring the host larvae. All enlarged.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration an

. Elementary plant physiology. Plant physiology. Nutrition. 97 and note the manner in which the fine hyphal threads of the parasite penetrate the cells of the host, or show de- vices for drawing nutritive material from them. Rusts, mildews, and molds will offer many accessible examples for such studies. 100. Symbiosis of a seed plant and a fungus Cut sections of the apical portions of the roots of any coniferous tree, and note the presence of a fungus which may enwrap the root in some species, replacing the piliferous layer, while in others it penetrates the cortical cells, send- ing hyphae ou Stock Photo

RMRE0KE0–. Elementary plant physiology. Plant physiology. Nutrition. 97 and note the manner in which the fine hyphal threads of the parasite penetrate the cells of the host, or show de- vices for drawing nutritive material from them. Rusts, mildews, and molds will offer many accessible examples for such studies. 100. Symbiosis of a seed plant and a fungus Cut sections of the apical portions of the roots of any coniferous tree, and note the presence of a fungus which may enwrap the root in some species, replacing the piliferous layer, while in others it penetrates the cortical cells, send- ing hyphae ou

. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PRELIMINARY NOTE ON NEW PROTOZOAN PARASITE. 40! the animal presents a smooth creamy-white appearance, or very rarely, a light brownish tinge. The latter color, however, is probably due to a staining action on the parasite of some sub- stance from the host. The large unattached end of the animal is bluntly rounded. At a greater or less distance from this end the body branches into two rami each of which is narrower than the main trunk (Fig. i). Each of the two primary rami branch again to form two smaller secondary rami. This Stock Photo

RMRHP6PW–. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PRELIMINARY NOTE ON NEW PROTOZOAN PARASITE. 40! the animal presents a smooth creamy-white appearance, or very rarely, a light brownish tinge. The latter color, however, is probably due to a staining action on the parasite of some sub- stance from the host. The large unattached end of the animal is bluntly rounded. At a greater or less distance from this end the body branches into two rami each of which is narrower than the main trunk (Fig. i). Each of the two primary rami branch again to form two smaller secondary rami. This

. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. 26 o})servati()n it is cvidciit tiiat the o-s (or iiiaj^-gots) of the parasite wcro placed upon the host (this grasshopper) previous to the third molt, and that the larval life of the parasite is at least as long as from May i^Â»j to August 28, or a period of nin(>ty-tive days. It is astonish- ing that all of the natural funetions of grasshoppers went on during this remarkal)le period of parasitic attack. Just to what extent the parasitic flies lessened the number of grasshoppers it is difficult to say owing t Stock Photo

RMRGWE7F–. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. 26 o})servati()n it is cvidciit tiiat the o-s (or iiiaj^-gots) of the parasite wcro placed upon the host (this grasshopper) previous to the third molt, and that the larval life of the parasite is at least as long as from May i^Â»j to August 28, or a period of nin(>ty-tive days. It is astonish- ing that all of the natural funetions of grasshoppers went on during this remarkal)le period of parasitic attack. Just to what extent the parasitic flies lessened the number of grasshoppers it is difficult to say owing t

. Bulletin of the U.S. Department of Agriculture. Agriculture; Agriculture. Fig. 29.— Chelonus shoshoneanorum: Adult female. Much enlarged. (Original.) explains its comparative immunity from the secondary parasite Dibrachys houcheanus. The adult feeds quite often at the oviposition wounds of its host. The adults are very hardy and the female is long Hved, One female lived from July 19 to September 21, 1914, a period of 64 days, and in this time 291 adults were reared from this one specimen. When the. Fig. 30.— Chelonous shoshoneanorum: Female ovipositing in egg of tuber moth. Much enlarged. (O Stock Photo

RMRGC6YR–. Bulletin of the U.S. Department of Agriculture. Agriculture; Agriculture. Fig. 29.— Chelonus shoshoneanorum: Adult female. Much enlarged. (Original.) explains its comparative immunity from the secondary parasite Dibrachys houcheanus. The adult feeds quite often at the oviposition wounds of its host. The adults are very hardy and the female is long Hved, One female lived from July 19 to September 21, 1914, a period of 64 days, and in this time 291 adults were reared from this one specimen. When the. Fig. 30.— Chelonous shoshoneanorum: Female ovipositing in egg of tuber moth. Much enlarged. (O

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