emery: SIMULIUM VITTATUM in KANSAS. 837 



inence of the thorax within the case. Plate XXXIX, figure 7, 

 shows a pupa with the imago within more developed and its 

 habit of withdrawing from the case as it matures. Plate 

 XXXIX, figure 8, shows a newly formed pupa removed from 

 its case; This shows the wing pads in their early develop- 

 ment. Plate XXXIX, figures 7 and 9, show lateral and dor- 

 sal views with the wing pads more developed. 



Emergence of the Adult. 



It is very interesting to watch the fly emerge from its pupal 

 skin. The skin is split longitudinally on the fore part of the 

 hump of the pupa. First the fly gets its head and fore legs 

 out, then by pulling itself forward it gets the middle legs and 

 part of the wings out, continues to crawl forward, freeing its 

 wings, hind legs, and abdomen. The whole process took about 

 five seconds on a stone that I held in my hand out of the water. 

 It left the old pupal skin fast in the case with the respiratory 

 filaments intact. 



Empty skins soon wash out of the their cases, which are 

 left as little tough empty pockets to fill with dirt and eventually 

 be washed away. 



Mr. E. C. O'Roke, in his field notes of the Entomological Sur- 

 vey, 1912, writes the following about newly emerged S/w «//»»?; 

 "They would dry their wings about five seconds, then fly." He 

 watched them emerge from a board which he held out of the 

 water. On the same survey Mr. F. X. Williams notes : "Almost 

 immediately on reaching the surface (of the water) the fly 

 (S. vittatum) would make efforts to rise on its still flexible 

 wings; sometimes, being unable to do so immediately, would 

 skim along the water for a way." His notes continued to say 

 that unless they arose after skimming and floating around a 

 short time they were devoured by some small fishes a few feet 

 below the place of emergence. Mr. H. R. Jennings, on the same 

 survey, notes : "The adult fly would first show up on the sur- 

 face of the water, having emerged from a pupa case among the 

 spirogyra, and then passed to a place free enough from spiro- 

 gyra to allow it to come to the surface. Once at the surface, the 

 fly would float on down the stream until it caught on the spiro- 

 gyra, and was there able to wait until its wings were thor- 

 oughly ready before attempting flight, or, if carried by the 

 current into a place free of spirogyra or other surface obstruc- 

 tions, the fly would, when permitted to float upon the surface 



