ORGANS OF DIGESTION. .ol 



sels (C. m.) From the chylific stomach the intestine con- 

 tinues downwards very narrow, and nearly straight, to a 

 short dilated colon (C. h.) which contracts before it termi- 

 nates in the cloaca. In the common blood-sucking bug, cirnex 

 lectularius (118, D.) the whole digestive apparatus is more 

 simple in its structure though more extended longitudinally, 

 the alimentary canal being about three times the length of 

 the short body of this insect. The mouth, armed with 

 piercing and sucking organs, receives the secretions of two 

 pairs of small salivary glands (D. n. o.) in form of simple 

 follicles terminated by minute vesicles at their closed ends- 

 The short capillary oesophagus forms a small conical crop 

 (D. c.) before entering the lengthened cavity of the chylific 

 stomach (D. e. f.) which is most dilated at its upper part 

 (D. e.) but is susceptible of considerable distension through- 

 out its whole course when filled with blood. The lower in- 

 testiniform portion of the chylific stomach, though here 

 represented for greater distinctness as drawn out nearly to 

 a straight course, is more convoluted in the short abdomen 

 of the living bug, and receives on each side at its narrow 

 pyloric termination (D./*.) the two orifices of short and sim- 

 ple hepatic vessels (D. m.) The remaining short and wide 

 intestine (D. h.) generally distended with a thick reddish- 

 brown coloured paste, the residue of digested blood, receives 

 obliquely the pyloric end of the stomach (D. f.) above and 

 contracts below into a narrow rectum before it terminates. 

 Although the biliary vessels (D. m.) here, as in most insects, 

 terminate in the stomach by separate orifices and without 

 cystic enlargements, distinct reservoirs for receiving and 

 collecting the bile are often developed at the insertion of 

 these tubes. In the pyrrhocoris aptera (Fig. 118. F.) which 

 feeds on the juices of the ripe fruits of malvacious plants, 

 and the intestinal canal of which, though more lengthened 

 and capacious, very much resembles in its whole structure 

 that of the cimex, the chylopoietic glands are much more 

 developed. There are three pairs of elongated salivary 

 glands opening into the mouth, and on the lower pyloric 

 extremity of the chylific stomach several minute simple pan- 

 creatic follicles (F. g.) are observed to open into its interior. 

 The biliary vessels (F. m.) are not only lengthened and wide, 

 but have thick glandular parietes, and they terminate on 



