9C8 



INSECTA. 



Lateral view of the alimentary canal of the larva of 

 Melolontha vulyaTis, with the three series of gastric 

 vessels. 



vessels the stomach is slightly constricted, and 

 receives the insertions of another set of coeca, 

 which differ from the last in being single, co- 

 nical, and directed backwards. At some dis- 

 tance beyond these, the stomach is encircled 

 by a third set of coeca, which differ from both 

 the preceding in being united in pairs at their 

 base, and inserted, with their apices directed 

 forwards, near the posterior part of the stomach. 

 Those cceca, both of the second and third 

 series, which are nearest to the upper part 

 of the stomach, are the shortest. These cceca 

 are not analogous to the hepatic vessels, or ra- 

 ther those usually so designated, but to the 

 gastric glands which cover the stomach in the 

 Carabida (Jig. 424) and Lucanida (Jig. 428), 

 and appear in this voracious larva designed to 

 secrete a fluid that may be necessary to enable 

 the stomach to digest the immense quantity of 

 vegetable matter taken into it. In the Lepi- 

 dopterous larvae the canal is scarcely more 

 developed than in the Coleopterous, since, 

 although the oesophagus is elongated, and 

 the larger intestines are somewhat more 

 complicated, no series of gastric glands are de- 

 veloped. We believe we have seen those which 

 surround the cardiac extremity in some ~Romby- 

 cld&j as in Odonestis potatoria, immediately 

 after the insect was killed, but merely as little 

 rounded protuberances, the character of which 

 was completely lost after the insect had been 

 preserved for a short time in spirits of wine. 

 They exist also very distinctly in the Sphinx. 

 In this order it commences by a distinct eso- 

 phagus (Jig. 364, c), which terminates by a val- 

 vular orifice in the third segment in a long and 

 very muscular stomach (C), around which the 

 six longitudinal bands are very distinct, as also 

 are the transverse muscular ones. At the com- 

 mencement of the eleventh segment it becomes 

 constricted, and terminates in a distinct pylo* 

 rus, which ends in a short ilium (e), into the 

 middle of which, on each side, are received the 





united termination of the hepatic vessels (f ) f 

 which, having extended along the sides of the 

 stomach as far forwards as the seventh segment, 

 are convoluted around this and the remaining 

 portion of the canal. Immediately behind the 

 ilium the canal is developed in a six double- 

 lobed ccecum (g), and immediately afterwards 

 into an immense sacculated colon (/*), termi- 

 nated by a very short rectum. The longitu- 

 dinal bands are particularly distinct on the 

 colon, and extend from its posterior part to the 

 external muscular tegument forming the retrac- 

 tors of the colon and rectum. In the active 

 larva of Coleoptera the alimentary canal be- 

 comes still more developed. It commences in 

 the larvae of the Carabid<e 9 Culosotna syco- 

 phanta (Jig. 426), according to Burmeister,* in 

 a very short oesophagus (II), 

 Fig. 426. that opens at the posterior 

 part of the pro-thoracic seg- 

 ment into a large cylindrical 

 stomach (K), which is ex- 

 r" l f fllfiff*^ tended throughout the great- 

 m<ljL er part of the body, very si- 

 milar in appearance to that 

 of the Lepidoptera. This 

 is called by Burmeister the 

 craw. It opens directly 

 into another cylindrical sto- 

 mach, much narrower and 

 nearly of the same length, 

 but more muscular than the 

 preceding, and receiving 

 its posterior extremity (Q),, 

 where it forms internally a 

 distinct pyloric valve, the 

 hepatic vessels. Burmeister 

 | A remarks that there is no 

 *vi valve of separation between 

 the first and second of these 

 stomachs, nor any rudiment 

 of the gizzard, which exists 

 in the perfect insects of this- 

 order (fig. 424, i). These 

 are succeeded by a small 

 intestine or ilium (L), 

 which is of some length, 

 and together with the se- 

 cond stomach forms several 

 convolutions in the body 

 between the first stomach, 

 or craw, and the great in- 

 testine or colon (M), which 

 follows it, and terminates 

 the canal in a protruded 

 Alimentary canal of anal aperture (O). The 

 colon, as in most larvae, is 

 very muscular and folded 

 transversely, and altogether 

 the canal is more developed than in the pre- 

 ceding instances, as also are its appendages 

 the hepatic vessels, which are exceedingly 

 long, although no cceca are developed upon 

 them. In the lihinchophora and Longicornes 

 there is a still higher form of alimentary canal, 

 as observed by Burmeisterf in Calandra 



* Transactions of Entomol. Society of London. 

 Vol. i. part 3. 



t Zur Naturgeschichte der Gattung Calandra. 

 Berlin, 1837. 



soma sycopJianta. 

 (Burmeister.) 



