File:Image from page 063 of "Introduction to zoology; a guide to the study of animals, for the use of secondary schools;" (1900) (14784607462).jpg

Identifier: introductiontozo00dave Title: Introduction to zoology; a guide to the study of animals, for the use of secondary schools; Year: 1900 (1900s) Authors: Davenport, Charles Benedict, 1866-1944 Davenport, Gertrude Anna Crotty, 1866- Subjects: Zoology Publisher: New York, Macmillan company London, Macmillian and co., ltd. Contributing Library: MBLWHOI Library Digitizing Sponsor: MBLWHOI Library

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Text Appearing Before Image: x);anterior wing with lancet-cell; hinder wingwith three root-cells . . Superfamily Phytophaga ^Plant-eating Hymenoptera) CHAPTER III THE BEETLE AND ITS ALLIES BEETLES (Coleoptera1) can be distinguished from otlieiinsects by the fact that the anterior pair of wings (elytra)are modified to form two horny shields, covering the pos-terior part of the body, while the posterior pair of wingsare membranous. The mouth parts are formed for biting.2 During development, the beetles, like the Lepidopteraand Hymenoptera, undergo great changes of form. Thesechanges may be observed in the potato-beetle. In thisspecies the orange-colored eggs are deposited often in avery regular manner on the under side of the potato leaf.Here they develop for several days. In about a week,however, the young, reddish, black-spotted larva, or grub,emerges. Like the adult beetle, it has three pairs of tho-racic legs. After feeding actively for two or three weeks,the larva descends into the ground, forms a naked yellow

Text Appearing After Image: FIG. 41. — Larva of Lachnosterna, the June bug, at roots of aster. Photo, of living animals, uat. size, by V. H. L. s, sheath ; 7rrep6v, wing.2 A key to some of the chief families of Coleoptera is given in the Appendix to this Chapter, page 58. 44 THE BEETLE AND ITS ALLIES 45 pupa, and emerges in about ten days as an imago. Fromtwo to four broods are produced during the year. Theadult beetles hibernate in the ground, emerging and layingeggs the following spring. The larval habits of the different kinds of beetles areextremely varied, quite as varied as the habits of the adult.The details of these differences may be best consideredwhen we take up the different kinds of beetles. The number of species of beetles which have been de-scribed is very great, probably over one hundred thousand.Of these, over ten thousand inhabit America, north ofMexico. Fortunately this vast number can be includedwithin a relatively small number of families. Leavingthe precise definition ofthese families to

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