File:Entomology - with special reference to its biological and economic aspects (1906) (14780758431).jpg

Identifier: entomologywit00fols (find matches)
Title: Entomology : with special reference to its biological and economic aspects
Year: 1906 (1900s)
Authors: Folsom, Justus Watson, 1871-1936
Subjects: Entomology
Publisher: Philadelphia : P. Blakiston's Son
Contributing Library: Robarts - University of Toronto
Digitizing Sponsor: University of Toronto

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B Terminal abdominal appendages of a dragon fly, Plathemis triinaculata. A, male;B, female. i, inferior appendage; s, s, superior appendages (cerci). The numbersrefer to abdominal segments. Thanaos, the claspers are peculiar in being strongly asym-metrical. In Odonata (Fig. 86, A) and Orthoptera, (Fig.87, A) the cerci of the male often serve as claspers. ANATOMY AND PHYSIOLOGY 73 In many insects the tergiim of the ^ast abdominal segmentforms a small siiraiial plate (Fig. 87, B, sp) ; this sometimes Fig. 87. 89 10 n 9 10 11
Text Appearing After Image:
Extremit)- of the abdomen of a grasshopper, Mclanopliis diitcrentialis. A, male;B, female. The terga and sterna are numbered, c, cercus; d, dorsal valves of ovi-positor; e, egg guide; p, podical plate; s, spiracle; sp, suranal plate; v, ventral valvesof ovipositor. supplements the claspers of the male in their function, as inLepidoptera (Fig. 85, A, s). 2. Integument Insects excel all other animals in respect to adaptive modi-fications of the integument. No longer a simple limitingmembrane, the integument has become hardened into an exter-nal skeleton, evaginated to form manifold adaptive structuressuch as hairs and scales, and invaginated, along with the un-derlying cellular layer, to make glands of various kinds. Chitin.—The skin, or cuticiila) of an insect differs fromthat of a worm, for example, in being thoroughly permeatedwith a peculiar substance known as chitin—the basis of thearthropod skeleton. This is a substance of remarkable sta-bility, for it is unaffected by almost

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