BTJCCAL APPARATUS OF INSECTS. 



99 



FIG. 322. TRUNK OF A 

 BUTTERFLY ; a, head ; 

 b, base of antennae; c, 

 eye ; d, trunk ; e, 

 palpi. 



FIG. 323. MORPHO HSLENOR. 



tongue. Sometimes this proboscis acquires an enormous length 

 (Fig. 321) ; sometimes on the contrary it is hardly visible. 

 Lastly, among the Butterflies, which are also supported on 

 liquid substances, but which find them at the bottom of the 



flowers, and there- 

 fore have no occa- 

 sion for instruments 

 to procure them, 

 there exist no setae 

 performing the func- 

 tions of lancets, as 

 among the preced- 

 ing ; and the mouth 

 is furnished with a 

 long tubular trunk, 

 coiled into a spiral, 

 and composed of 

 two slender filaments, each channelled on its internal edge, so 

 that a tube is formed by the adhesion of the two ; these are 

 nothing else than the maxillge very greatly lengthened and 

 modified in their form. At the base of this tube is seen a 

 small membranous piece, which is the representative of the 

 labrum ; and on each side, a small tubercle, the only vestige 

 of the mandibles. We also perceive the rudiments of the 

 maxillary palpi ; and behind is found a small triangular labium, 

 having two very large labial palpi, composed of three joints, and 

 nearly always clothed with scales. 



617. The alimentary canal generally presents a very com- 

 plicated structure : sometimes it is straight, and has very nearly 

 the same diameter throughout its entire length ; but usually it 

 is more or less convoluted, and has several successive enlarge- 

 ments, and contractions. We may distinguish in it (Fig. 324), 

 a pharynx (a), an oesophagus (5), a first stomach or crop (c), a 

 second stomach or gizzard (d) 9 of w.hich the walls are muscular 

 and often armed with horny pieces fitted to triturate the food ; 

 a third or true digestive stomach (e), whose texture is soft and 

 delicate ; a small intestine (/), a ccecum, and a rectum (g). As 



H2 



