. Elementary entomology. Insects. HYMENOPTERA 249 upon or within a larva or an egg, the larger forms laying but a single egg on a larva, while the smaller species may deposit a con- siderable number within a large caterpillar. The young larva at once enters the body of the host and feeds upon its blood, not interfering with the principal tis- sues and-organs, so that the host goes on growing and furnishing food to the parasite. Finally, however, the parasite so depletes the vitality of the host that it dies, though often not until it has transformed to a pupa. The parasitic larva then spins it
. Elementary entomology. Insects. HYMENOPTERA 249 upon or within a larva or an egg, the larger forms laying but a single egg on a larva, while the smaller species may deposit a con- siderable number within a large caterpillar. The young larva at once enters the body of the host and feeds upon its blood, not interfering with the principal tis- sues and-organs, so that the host goes on growing and furnishing food to the parasite. Finally, however, the parasite so depletes the vitality of the host that it dies, though often not until it has transformed to a pupa. The parasitic larva then spins its co- coon, usually either \vithin or upon the dead host, and in due time the adult parasite emerges and continues the good work. To a. FlG. 394. Long-tailed ichneumon-fly (Thalessa lunator}. (Natural size) The parts of the long ovipositor normally lie together as a single organ ; the figure at the left shows the manner of inserting the ovipositor in wood. (After Comstock) certain extent many parasites are peculiar to certain host insects, though many of them attack various larvae or caterpillars having similar habits. Frequently many of our worst insect pests are brought under control by the beneficent work of these little parasites,. 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 perfectly resemble the original Sanderson, Dwight, 1878-1944; Jackson, C. F. (Cicero Floyd), b. 1882. Boston, New York [etc. ] Ginn and Company
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