. Entomology : with special reference to its biological and economic aspects. tes belong to the two most specialized orders,Diptera and Hymenoptera. The larvje of Bombyliidre feed upon the eggs of Orthop-tera and upon larvae of Lepidoptera and are the most important dipterous parasites of otherinsects and lay their eggs most frequently upon caterpillars;the larvse bore into their victim, develop within its body, andat length emerge as winged insects. These parasites oftenrender an important service to man in checking the increaseof noxious Lepidoptera. The great majority
. Entomology : with special reference to its biological and economic aspects. tes belong to the two most specialized orders,Diptera and Hymenoptera. The larvje of Bombyliidre feed upon the eggs of Orthop-tera and upon larvae of Lepidoptera and are the most important dipterous parasites of otherinsects and lay their eggs most frequently upon caterpillars;the larvse bore into their victim, develop within its body, andat length emerge as winged insects. These parasites oftenrender an important service to man in checking the increaseof noxious Lepidoptera. The great majority of insect parasites—many thousandspecies—belong to the order Hymenoptera, constituting oneof the primary divisions of the order. They are immensely 3IO ENTOMOLOGY important from an economic standpoint, particularly the Ich-nenmonid^, of which more than ten thousand species are al-ready known. Our most conspicuous ichneumonids are thetwo species of Thalcssa, T. atrafa and T. liiiiafor (Fig. 271),with their long ovipositors (three inches long in liiiiator, and Fig. Oviposition of Thalcssa lunator. Natural size.—After Riley. four to four and three quarters inches in of rata). Thalcssabores into the trunks of trees in order to reach the burrows ofanother large hymenopteron, Trcuicx cohunlm (Fig. 31). uponwhose larv?e the larva of Thalcssa feeds. The enormous family Braconid?e, closely related to Ichneu-monidcT, is illustrated by the common Apantclcs coiigrcgatus,which lays its eggs in the caterpillars of various parasitic larv?e feed upon the l)lood and possibly also thefat-body of their host, and at length emerge and spin their co-coons upon the exterior of the caterpillar (),sometimesto the number of several hundred. Species of Aphid ins trans-form within the bodies of plant lice, one to each host, and theimago cuts its way out through a circular opening with a cor-respondingly circular lid. Chalcidid;e, of which some fourthousand species are kn
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectentomology, bookyear1
