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Annals Entomological Society of America [Vol. VI, 



brown in thirteen days; pigment appears in the wings at the 

 end of thirteen days in the center of the segments of the abdomen 

 in two weeks. Pigmentation is apparently complete in about 

 sixteen to eighteen days (July 13 to Aug. 3). 



Figures 11-14. Late larvee and pupal stages. 

 Full grown larva showing the leg buds; enlarged five times. 

 Side view of the pupa; enlarged five times. 

 Front view of the anterior end of a fly pupa. 

 Front view of the posterior end of the same. 



Some time soon after the pigment is completely developed, 

 the pupa begins to. use the hooks for digging. In this process 

 the numerous long stiff bristles arranged in a ring about the 

 segments and projecting backward are of much importance for 

 they tend to make simple movements either push the 

 body forward or push loose sand backward. The large U- 

 shaped bristles along the dorsal side may or may not function in 

 this way also. The main digging operations are carried on by 

 means of the hooks on the head. The two spines of the poster- 

 ior end serve as anchoring organs. The body is curved dorsal- 

 ward in the form of a bow with the dorsal side pressed against 

 the upper side of the burrow. The U-shaped bristles prom- 

 inent upon the dorsal side may function as anchors in this 



