3.76. KANSAS UNR'ERSITY SCIENCE BULLETIN. 



the thorax, being at this point little larger than the nerve cord 

 just below it. Upon reaching the thorax it may change its 

 direction slightly and continue its way through the thorax to 

 the abdomen, or it may make a sudden bend dorsally and as 

 abruptly bend back again, then continuing its course from 

 there on as in the other case. In any event the slender por- 

 tion of the tube suddenly enlarges, forming a tube of three 

 times its diameter, the union of these two parts being marked 

 by an enlargement, or a series of three enlargements. From 

 the ventral side of this enlargement there arises a thin-walled 

 duct (Fig. 11, PI. XLV) that leads backward beneath the canal 

 and expands into a rather large pouch. This duct can not 

 strictly be defined as such, for it is simply the cephalic end of 

 a sac which gradually narrows till it joins the digestive canal 

 at the point shown in the figui-e (Fig. 11). The walls of this 

 pouch are extremely thin and transparent when distended and 

 at such times it occupies a considerable space in the abdomen. 

 As shown in fig. 11 Fr. and in fig. 2 Fr. the pouch is some- 

 what contracted and shows muscle fibres. This sac by virtue 

 of its position and union with the proventriculus leads to the 

 conclusion that it must function as a food reservoir.* 



The Stomach. The digestive tract upon passing into the 

 abdomen usually turns dorsally for a short distance, where it 

 enlarges to form an oval-shaped organ, the ventriculus or 

 stomach. No ccecal tubesf have been found, but the surface 

 of this mid-intestine is somewhat irregular, and it may be that 

 the glandular areas in the wall of this organ will prove to 

 function as coecal glands.J 



Malpighiau Tubes. Immediately below the mid-gut there 

 arise on either side two tubes. These four tubes are of con- 

 siderable length, and lie folded and doubled back on them- 

 selves above the mid-intestine and above and around the hind 

 gut. These are the Malpighian tubules. Their natural position 

 in the body is shown in fig. 2 pi. XLIII. Each tubule extends 

 forward to cephalic end of stomach where, after making a 

 loose double loop, it turns back to end with a half turn around 

 rectal pouch. They are best studied in the male and freshly 

 emerged female or in specimens treated for some time in 15 



* Gordon Hewitt refers to a similar organ in the house fly as the crop. 



t They are recorded as present in the larva of Simulium by iiiall and Hammond. 



t Haseman, 1910, considers a group of cells in the region of OBSophageal valve of 

 Psychola alternata as a reduced coecal gland. 



