CLASS INSECTS. 



1 383 



maxillary palpi, and behind is found a small triangular 

 lip carrying two very large labial palpi, composed of three 

 joints, and almost always velvety and covered with scales (e). 

 525. The alimentary canal presents in general a suf- 

 ficiently complex structure ; sometimes it is straight, and offers 

 pretty nearly the same diameter throughout its whole length ; 

 but in general it is more or less flexuous, and has several 

 successive enlargements and contractions. We distinguish, 

 then (Fig. 365), a pharynx, a gullet, a first stomach or crop, 

 a second stomach or gizzard, whose walls are muscular, and 

 often provided with horny parts adapted "to triturate the 

 food; a third stomach, called the chylifying stomach, whose 



Fig. 363. Proboscis 

 of a Butterfly.* 



Fig. 364. Marpha Helenor, 

 (Vampa). 



texture is soft and delicate ; a small intestine, a caecum, and 

 a rectum. As in the superior animals, we observe a relation 

 between the nature of the food and the development the canal 

 requires ; in carnivorous insects it is in general very short, 

 whilst in insects which are nourished on vegetable sub- 

 stances it is in general very long. The food which reaches 

 it is imbibed with saliva ; the apparatus which secretes this 

 liquid consists in a certain number of floating tubes, ter- 

 minating sometimes by kinds of utricles, and communi- 

 cating with the pharynx by excretoiy canals. A multitude 



* a, head ; 6, base of the antennae or feelers ; c, the eye ; d, the pro- 

 boscis ; e, palpi. 



