A text-book of entomology, including the anatomy, physiology, embryology and metamorphoses of insects, for use in agricultural and technical schools and colleges as well as by the working entomologist . t the elytra are opened so as to form an THE ELYTRA 125 angle with the body and admit of the free play of the wings(Kirby and Spence). In the running beetles (Carabidae), also in theweevils and in many Ptinidae, the hind wings are wanting, throughdisuse, and often the elytra are firmly united, forming a single hardshell or case. The firmness of the elytra is due both to the thick-ness of the ch
A text-book of entomology, including the anatomy, physiology, embryology and metamorphoses of insects, for use in agricultural and technical schools and colleges as well as by the working entomologist . t the elytra are opened so as to form an THE ELYTRA 125 angle with the body and admit of the free play of the wings(Kirby and Spence). In the running beetles (Carabidae), also in theweevils and in many Ptinidae, the hind wings are wanting, throughdisuse, and often the elytra are firmly united, forming a single hardshell or case. The firmness of the elytra is due both to the thick-ness of the chitinous deposit and to the presence of minute chitinousrods or pillars connecting the upper and lower chitinous surfaces. Hoffbauer finds that in the elytra of beetles of different familiesthe venation characteristic of the hind wings is wanting, the maintracheae being irregular or arranged in closely parallel longitudinallines, and nerve-fibres pass along near them, sense-organs being alsopresent. The fat-bodies in the cavity of the elytra, which is linedwith a matrix layer, besides nerves, tracheae, and blood, contain se-cretory vesicles filled with uric-acid concretions such as occur in the u. FIG. 139.—Longitudinal section through the edge of the elytrum of Lina (?nea : gl, glands;r, reservoir; fb, fat-body ; m, matrix ; >i, upper, — /, lower, lamella. — After Hoffbauer. fat-body of Lampyris. There are also a great many glands varyingmuch in structure and position, such occurring also in the pronotum(Fig. 139). Meinert considers the elytra of Coleoptera to be the homologues of the tegulteof Lepidoptera and of Hymenoptera. He also calls attention to the alulaobserved in Dyticus, situated at the base of the elytra, but which is totallycovered by the latter. The alulte of these beetles he regards as the homologuesof the anterior wings of Hymenoptera and Diptera. No details are given insupport of these views. (Ent. Tidskrift, i, 1880, p. 168.) Hoffbauer (181)2) also ha
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishe, booksubjectinsects
