Sacculina is a genus of barnacles that parasitize crabs. The female Sacculina larva finds a crab and walks on it until it finds a joint. It then molts, injecting its soft body into the crab while its shell falls off. The Sacculina grows in the crab, emerging as a sac, known as an externa, on the underside of the crab's rear thorax, where the crab's eggs would be incubated. Here the parasite has been removed from the crab.

Crustacean Parasite

Sacculina is a genus of barnacles that parasitize crabs. The female Sacculina larva finds a crab and…

The Blackberry Psyllid (Trioza tripunctata) is an insect that feeds on specific plants.

Blackberry Psyllid

The Blackberry Psyllid (Trioza tripunctata) is an insect that feeds on specific plants.

"About a foot long, and is provided with a pwerful sucker on the top of its head, by which it attackes itself to rocks, ships, and even large fishes." — Goodrich, 1859

Remora

"About a foot long, and is provided with a pwerful sucker on the top of its head, by which it attackes…

"A parasitic isopod crustacean, Aega psora, and some similar forms." -Whitney, 1911

Salve Bug

"A parasitic isopod crustacean, Aega psora, and some similar forms." -Whitney, 1911

A parasite which feeds as larvae in rose-twigs or upon the leaves. Some species are confined to roses for their food, while others can also feed on other plants.

Larvae of Rose Sawfly

A parasite which feeds as larvae in rose-twigs or upon the leaves. Some species are confined to roses…

Scelio is a genus of parasitic insects of the Proctotrypidae family. "Scelio famelicus. a, female; b, her antenna." -Whitney, 1911

Scelio

Scelio is a genus of parasitic insects of the Proctotrypidae family. "Scelio famelicus. a, female; b,…

An illustration of the median longitudinal section through anterior end of the sea lamprey. "a.v.o, Antrio-ventricular opening; br, Brain; br.o, Internal opening of gill sac; d.a, Dorsal aorta; d.c, Ductus cuvieri; h.v, Hepatic vein; i.j.v, Inferior jugular vein; N, Notochord; oes, Esophagus; olf, Olfactory organ; oc, Pericardium; p.c.v, Left posterior cardinal vein; pit, Pituitary tube; V, Ventricle; v, Velum." (Britannica, 1910)

Cross Section View of a Sea Lamprey

An illustration of the median longitudinal section through anterior end of the sea lamprey. "a.v.o,…

"Four inches long; found in the European seas." — Goodrich, 1859

Sea-snail

"Four inches long; found in the European seas." — Goodrich, 1859

"Resplendent Shield-bearer (Coptodisca splendoriferella). a, leaf of apple showing work; b, summer larva; c, larva in case, traveling; d, cases tied up for winter; e, hibernating larva; f, pupa; g, moth; h, parasite: all enlarged." -Whitney, 1911

Resplendent Shield Bearer

"Resplendent Shield-bearer (Coptodisca splendoriferella). a, leaf of apple showing work; b, summer larva;…

Spore of a bread fungus mold

Bread fungus mold spore

Spore of a bread fungus mold

"Two secondary spores joined"—Finley, 1917

Joined spores

"Two secondary spores joined"—Finley, 1917

"Cattle Tick. Above, nat. size, side view; below, dorsal view, enlarged." -Parker, 1900

Cattle Tick

"Cattle Tick. Above, nat. size, side view; below, dorsal view, enlarged." -Parker, 1900

"Trichina Spiralis is the name given to a peculiar nematoid worm which inhabits the muscles, usually of the pig. The viviparous females, originally living in rats, being about eight days after entering the intestines of their second host, a pig, to give birth to the larvæ, which pass into various parts of the body, especially the muscles, where they coil up in a sack, or cyst, which eventually becomes calcareous and whitish. When pork thus infected is eaten the worms are set free in the stomach of their third host (man), and in three or four days there become sexually mature, each female being capable of producing 1,000 young."—(Charles Leonard-Stuart, 1911)

Trichina Spiralis

"Trichina Spiralis is the name given to a peculiar nematoid worm which inhabits the muscles, usually…

"Trichina Spiralis is the name given to a peculiar nematoid worm which inhabits the muscles, usually of the pig. The viviparous females, originally living in rats, being about eight days after entering the intestines of their second host, a pig, to give birth to the larvæ, which pass into various parts of the body, especially the muscles, where they coil up in a sack, or cyst, which eventually becomes calcareous and whitish. When pork thus infected is eaten the worms are set free in the stomach of their third host (man), and in three or four days there become sexually mature, each female being capable of producing 1,000 young."—(Charles Leonard-Stuart, 1911)

Trichina Spiralis

"Trichina Spiralis is the name given to a peculiar nematoid worm which inhabits the muscles, usually…

"1. Trypanosoma gambiense, showing nucleus, blepharoplast, and flagellum. 2 and 3. Individuals undergoing longitudinal fission. 4. Leucocyte engulfing a trypanosome." -Thomson, 1916

Trypanosoma Gambiense

"1. Trypanosoma gambiense, showing nucleus, blepharoplast, and flagellum. 2 and 3. Individuals undergoing…

The cocoon of Sigalphus curculionis, a species of parasitoid wasps. These insects use other insects as hosts until they are eventually killed.

Parasite Wasp Cocoon

The cocoon of Sigalphus curculionis, a species of parasitoid wasps. These insects use other insects…

The larva of Sigalphus curculionis, a species of parasitoid wasps. These insects use other insects as hosts until they are eventually killed.

Parasite Wasp Larva

The larva of Sigalphus curculionis, a species of parasitoid wasps. These insects use other insects as…

The pupa of Sigalphus curculionis, a species of parasitoid wasps. These insects use other insects as hosts until they are eventually killed.

Parasite Wasp Pupa

The pupa of Sigalphus curculionis, a species of parasitoid wasps. These insects use other insects as…

The female adult of Sigalphus curculionis, a species of parasitoid wasps. These insects use other insects as hosts until they are eventually killed.

Female Adult Parasite Wasp

The female adult of Sigalphus curculionis, a species of parasitoid wasps. These insects use other insects…

The male adult of Sigalphus curculionis, a species of parasitoid wasps. These insects use other insects as hosts until they are eventually killed.

Male Adult Parasite Wasp

The male adult of Sigalphus curculionis, a species of parasitoid wasps. These insects use other insects…

Eucharis americana is an insect in the Chalcididae family of parasitic wasps.

Chalcid Wasp

Eucharis americana is an insect in the Chalcididae family of parasitic wasps.

Eupelmus floridanus is a species of Chalcid wasp, a parasitic insect in the Eupelmidae family.

Chalcid Wasp

Eupelmus floridanus is a species of Chalcid wasp, a parasitic insect in the Eupelmidae family.

The Ichneumon wasp is a parasitoids, where the larvae feed on another insect until it dies.

Ichneumon Wasp

The Ichneumon wasp is a parasitoids, where the larvae feed on another insect until it dies.

Encyrtus cecidomyiae is a species of wasp in the Encyrtidae family of parasitic wasps.

Parasitic Wasp

Encyrtus cecidomyiae is a species of wasp in the Encyrtidae family of parasitic wasps.

"The Whale-Louse, <em>Cyamus seti</em>, is found on whales along our coasts." &mdash; Goodrich, 1859

Whale-louse

"The Whale-Louse, Cyamus seti, is found on whales along our coasts." — Goodrich, 1859

A longitudinal section of of smutted wheat.

Smutted wheat

A longitudinal section of of smutted wheat.

A cross-section of wood infested with insects.

Infested wood

A cross-section of wood infested with insects.