352 ORGANS OF DIGESTION'. 



each side in a single vesicular enlargement or gall-blad- 

 der (F. /.) before entering the stomach, which is here suc- 

 ceeded, as in the former insect, only by a short and capacious 

 colon (F. h.} and narrow tapering rectum. In the geocorises all 

 the lateral hepatic vessels terminate in a single median gall- 

 bladder. In the mandibulate herbivorous insects, which sub- 

 sist on coarser vegetable food, as the common coleopterous 

 cockchaffer, melolontha vulgaris (Fig. 116. A.) which feeds on 

 the leaves anil shoots of our garden plants, the whole digestive 

 apparatus is long, complicated, and capacious. The oesophagus 

 passes out narrow from the head (A. a.) and dilates below 

 into a short conical crop (A. c), which is succeeded by a very 

 minute gizzard (A. d.) and a long convoluted chylific stomach 

 (A. d. e. e. /.). The anterior portion of this lengthened 

 glandular stomach is wide and sacculated by numerous 

 transverse strictures, and terminates insensibly in a narrow 

 convoluted pyloric part, which dilates into a small round 

 vesicle at the lower end, where it receives the openings of 

 the hepatic vessels (A./ 1 .). The two hepatic vessels (A. i. I. 

 m.) on each side are here, in accordance with the coarse 

 nature of the vegetable food, very long, wide, and convoluted, 

 and have their secreting surface greatly extended by the 

 development of innumerable small lateral follicles (A. i. k. I.) 

 which give them a pinnated form throughout the greater 

 part of their course ; thus presenting the most complicated 

 condition of the liver met with in insects. The lower portion 

 of the intestinal canal has also its capacity increased by 

 distinct dilatations on the parts analogous to the colon 

 (A. g.) and the rectum (A. m.} In the powerful, aquatic, 

 insectivorous naucoris aptera (Fig. 118. E.) the whole form 

 of the digestive organs closely resembles that of the cimex, 

 but there is a short, narrow, small intestine between the 

 chylific stomach (E. e.) and the colon, the pyloric end of 

 the stomach dilates, as in many insects, into a small oval 

 sac where it receives the hepatic vessels, the cardiac part 

 of the stomach is wide and partially sacculated, and the 

 crop (E. c.) forms an almost imperceptible dilatation at the 

 lower end of a small elongated oesophagus. The posterior pair 

 of salivary glands (E. p.) form wide cylindrical tubes which 

 terminate by short narrow ducts in the mouth, and the two 

 anterior shorter pairs (E. o. n.) divide at their closed extremities 



