. Elementary zoology. Zoology. 2T4 ELEMENTARY ZOOLOGY r%.. plete metamorphosis, and their habits and instincts are, as a rule, very highly specialized. The parasitic Hymen- optera such as the ichneumon flies, chalcid flies, etc., are stingless but have usually a piercing ovipositor (the sting being only a modified ovipositor). The general life-history of these ichneumons is as follows: the female ichneumon fly, finding one of the caterpillars or fly or beetle larvae which is its host, settles on it and either lays an egg or several eggs on it, or thrusting in its ovi- positor, lays the eggs in
. Elementary zoology. Zoology. 2T4 ELEMENTARY ZOOLOGY r%.. plete metamorphosis, and their habits and instincts are, as a rule, very highly specialized. The parasitic Hymen- optera such as the ichneumon flies, chalcid flies, etc., are stingless but have usually a piercing ovipositor (the sting being only a modified ovipositor). The general life-history of these ichneumons is as follows: the female ichneumon fly, finding one of the caterpillars or fly or beetle larvae which is its host, settles on it and either lays an egg or several eggs on it, or thrusting in its ovi- positor, lays the eggs in the body; the young ichneumon hatching as a grub burrows into the body of its caterpillar host, feeding on the body- tissues, but not attacking the heart Fig. , the or nervous system, so that the host larva 01 the predaceous J water-beetle, Dyticus sp. is not soon killed; the ichneumon (From specimen.) pupates either inside the host, or crawls out and, spinning a little silken cocoon (fig. 160), pupates on the surface of the body or elsewhere. Some of the stingless Hymen- optera are not parasites, but are gall-producers. The female with its piercing ovipositor lays an egg in the soft tissue of a leaf or Fig. 78.—The plum curculio, Stem, and after the larva hatches Conotrachelusnenuphar a beetle very injurious to plums. the gall rapidly forms. The (Photograph by M. V. Sim- larval insect lies in the plant- an °* tissue, having for food the sap which comes to the rapidly growing gall. It pupates in the gall, and when adult eats its way 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 Kellogg, Vernon L. (Vernon Lyman), 1867-1937. New York : H. Holt and company
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1902
