— 34 — 



Proventriculus. — In the caudal part of the thorax the ali- 

 mentary canal begins to enlarge. This enlargement increase 

 gradually caudad until, in the first or second abdominal 

 segment, its diameter is' twice that of the oesophagus ; 

 then it contracts quite suddenly until its diameter is 

 less than that of the oesophagus ; this enlarged portion is 

 the proventriculus. It corresponds in function with the giz- 

 zard of birds and is very complicated in structure internally. 



Ventriculiis . — Caudad of the constriction following the pro- 

 ventriculus, there is a slightly enlarged portion, from the 

 cephalic end of which, there project cephalad, four large 

 pouches ; this enlargement is the ventriculus or stomach and 

 the pouches are the gastric ca?ca. The two caeca of each 

 side are quite closely united. 



Malpighian vessels. — Emptying into the caudal end of the 

 veutriculus are several, small, very long, and much convo- 

 luted tubes ; these are the Malpighian vessels ; they were 

 named in honor of Malpighi, one of the early anatomists. 

 As uric acid is found in the Malpighian vessels, they are sup- 

 posed to correspond to the kidneys in function. 



Determine the number of Malpighian vessels. 



Intestine. — The part of the alimentary canal extending 

 from the veutriculus totlie caudal end of the bod}* is the 

 intestine ; the part imrUPktely caudad of the veutriculus is 

 the small intestine ; following the small intestine is the large 

 intestine ; there are two bends in the cephalic part of the 

 large intestine ; the first extends dorsad and cephalad ; the 

 second, dorsad and caudad ; the rectum is not a well-defined 

 part of the intestine in this insect. 



Attachments of the Alimentary Canal. — The alimen- 

 tary canal is attached to the body-wall and thus held in 

 place in various ways. The most obvious attachments are 

 those of the ends of this organ. In addition to these direct 

 connections, the alimentary canal is indirectly connected to 

 the body-wall as follows : — 



