228 Annals Entomological Society of America [Vol. XIII, 



face of the posterior crop but is chiefly confined to its ventral 

 surface. Following the intestine backward it may be traced to 

 the posterior boundary of the sixth abdominal segment where 

 it takes a dorsal course toward the rectum. As in the case of 

 the descending intestine, a knot or coil is formed (Figs. 1, 2 

 and 3, k) but when the tube emerges from the coil, it turns 

 anteriorly and connects with the posterior crop at the extremity 

 of the latter (Figs. 1 and 2, x). 



The posterior crop is one of the most puzzling divisions of 

 the tube at first sight. It is enormously developed, especially 

 in the adult male during later life, and its gradual enlargement 

 from the period of emergence to late life is one of the anomalies 

 demanding adequate explanation. Because of the thinness of 

 parts of its walls its true nature might be unsuspected if one 

 depended upon gross dissections alone. In the adult male it 

 extends from the metathorax to the end of the sixth abdominal 

 segment (Figs. 1, 2 and 3, pc). An anterior caecal prolongation 

 extends forward beneath the crop as indicated in Fig. 3. Its 

 main portion gradually enlarges posteriorly except for indenta- 

 tions at the boundaries of one or two segments until, beginning 

 in the region of the second abdominal segment, its walls closely 

 approximate the chitinous integument on all sides. The small 

 intestinal tubes connecting fore and aft with the internal gland 

 run their courses upon its outer surface as indicated above. 



The rectum is confined usually to the last two abdominal 

 segments (Figs. 1, 2, 3, r). It is an elongated sac with numerous 

 longitudinal folds and lies close to the dorsal integument. It 

 is easy to understand how some writers may have gotten the 

 impression that the digestive tube of the male insect did not 

 have any complete posterior portion, for in all cases where a 

 dissection is attempted from the dorsal side the rectum is 

 destroyed. It is practically impossible to remove any part of 

 the dorsal integument in this region without injuring the 

 underlying rectal sac. It can be exposed, however, by care- 

 fully dissecting from the ventral side, through the mass of 

 coiled reproductive ducts and fat. 



The foregoing description is based entirely upon observa- 

 tions in the adult male insect. While the female organs are 

 arranged on the same general plan, there are slight variations 

 and these will be mentioned in another place. 



