The insect world : being a popular account of the orders of insects, together with a description of the habits and economy of some of the most interesting species / by Louis Figuier.

  • Louis Figuier
Date:
[1872]
Catalogue details

Licence: Public Domain Mark

Credit: The insect world : being a popular account of the orders of insects, together with a description of the habits and economy of some of the most interesting species / by Louis Figuier. Source: Wellcome Collection.

    24/558 page 10
    Fig. io, which represents the digestive apparatus of Carabui anratus, a common beetle, présents to the eyes of the reader the different organs of which we are speaking. a is the mouth of the insect, b the œsophagus, c the crop, d the gizzard, e the chylific ventricle, F and G the small and large intestines, and h the anus. It is not necessary to consider the other parts of the alimentary canal in insects, but only to refer to some of the appendages of this apparatus. The salivary glands pour into the di- gestive tube a liquid, generally colourless, which, from the place where it is secreted, and its alkaline nature, corresponds to the saliva in vertebrate animais. It is this liquid which cornes from the tongue of sucking insects in the form of drops. These glands are always two in number. Their form is as variable as complicated. The rnost simple is that of a closed flexible tube, generally rolled into a bail, and open- ing on the sides of the œsophagus. At the posterior extremity of the chylific ventricle are inserted a variable number of fine tubes, usually elongated and flexible, and terminating in culs-dc-sac at one end. Their colour, which dépends on the liquid they may contain, is sometimes white, but more frequently brown, blackish, or green. They appear to be composed of a very slight and délicate membrane, as they are very easily torn, and nothing is more diffi- cult than to unroll and to disengage them from the fatty or other tissues by which they are enveloped. The function of these vessels is uncer- chy i i fie vëttiI d e °su rr o mid b y t h c tain. Cuvier and I.éon Dufour supposed Maipîghian vessels. them to be analogous to the liver, and on that account they hâve been called biliary vessels ; and they are often termed the Malpighian vessels, after the name of their discoverer. According to M. Lacordaire, their functions van' with their
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