Elementary text-book of zoology (1884) Elementary text-book of zoology elementarytextbo0101clau Year: 1884 530 INSECTA. cavity, open one or more pairs of tubular or racemose salivary glands (8p). In many of the suctorial insects, the end of the oesophagus is dilated into a sack with thin membranous walls and a short stalk, the suctorial stomach ; in others into a more uniform dilatation, known as the crop (tig. 439, Oe). The intestine which follows the oesophagus is sometimes straight and sometimes coiled ; it varies exceedingly in accordance with the mode of life. It is always at least divis
Elementary text-book of zoology (1884) Elementary text-book of zoology elementarytextbo0101clau Year: 1884 530 INSECTA. cavity, open one or more pairs of tubular or racemose salivary glands (8p). In many of the suctorial insects, the end of the oesophagus is dilated into a sack with thin membranous walls and a short stalk, the suctorial stomach ; in others into a more uniform dilatation, known as the crop (tig. 439, Oe). The intestine which follows the oesophagus is sometimes straight and sometimes coiled ; it varies exceedingly in accordance with the mode of life. It is always at least divisible into a longer portion, which is concerned in di gestion, the mesenteron or chi/Ufic ventricle (M, CJid), and a terminal portion, which is concerned with the ejection of the freces (figs. 439, 440). The number of regions may, however, be larger. In predaeeous Insects, especially in the orders of Coleoptera and Neuroptera, a masticatory stomach or proventriculus (fig. 440, Pr) is inserted between the crop and chylinc ven- tricle ; this is of globular form, and has powerful muscular walls. It is lined by a specially thick chitin- ous cuticle, which is beset with strong bands, teeth, and bristles. The chylinc ventricle also, 011 which especially the digestive glandular layer is developed at the expense of the mus- cular layer, is sometimes divided into several re- gions, as for example in FIG. 439.—Digestive apparatus of A/iis uieHiflca (after Leon Dufour). S/>, Salivary glands; OP, ffiso- phagus with crop-like dilatation ; M, chylinc ven- tricle ; Re, Malpighiau vessels; If, rectum with so-called rectal glands ; G. Dr, poison glands. some Beetles the anterior part has a shaggy appearance from the numerous ca?ca which project from it (fig. 440 CM}, and is sharply marked oft' from
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