262 



INSECTA. 



its introduction into the digestive stomach. In order to effect this, 

 it is lined internally with a dense cuticular membrane, and occa- 

 sionally studded with hard plates of horn or strong hooked teeth, 

 adapted to crush or tear in pieces whatever is submitted to their 

 action. 



When bruised in the gizzard, the food passes on into the proper 

 stomach, which is generally a long intes Uniform organ (Jig. 116, 

 d, d), extending from the crop or gizzard to the point where the 

 biliary vessels discharge themselves into the intestine. The size 

 and shape of this organ will vary of course with the nature of the 

 food. Thus, in the butterfly (Jig. 117, &), which scarcely eats 

 at all, or sparingly sips the honey from the flowers, it is very mi- 

 nute ; but, in insects which live upon coarse and indigestible mate- 

 rials, it is proportionately elongated and capacious. 



(304.) The stomach generally ends in the Small Intestine (Jig. 

 116, e ; 117, *), but this is occasionally entirely wanting, so that the 

 stomach seems to terminate immediately in the colon or large intes- 

 tine, which is the terminal portion of the alimentary canal : when 

 much developed, the small intestine is sometimes divided by a con- 

 striction into two parts, to which the names of Duodenum and Ilium 

 have been applied by entomological writers. The colon (fig. 



Fig. in. 



116,y; 117, k) is separated 

 from the small intestine by 

 a distinct valve; and, in con- 

 nection with its commence- 

 ment, a wide blind sacculus 

 or caecum is often met with. 



(305.) We may now no- 

 tice the secern ing organs that 

 pour fluids in to different parts 

 of the digestive apparatus ; 

 beginning with those which 

 open into the oesophagus in 

 the vicinity of the mouth, 

 and examining them in the 

 order of their occurrence as 

 we proceed backwards. 



The first are the salivary 

 vessels, which terminate in 

 the neighbourhood of the 

 mouth itself, into which they seem to pour a secretion analogous to 



