84 Psyche [June 



no reason to suppose that the development of the entomophilous 

 flora would have varied in any respect had entomophily never 

 arisen among the Coleoptera. 



TABLE OF NORTH AMERICAN SPECIES OF THE DIP- 

 TEROUS GENUS THRYPTICUS, WITH DESCRIP- 

 TIONS OF FOUR NEW SPECIES. 



By Millard C. Van Duzee, 

 Buffalo, New York. 



While studying the Thrypticus in my collection and a little mate- 

 rial that came to hand I found four forms that seem to be new. 

 These are described below. 



In wilUstoni Wh. the fore and middle coxse may be mostly 

 yellow or infuscated almost to the tips, while in the female they 

 may be somewhat blackened. This seems to be our most abun- 

 dant species in western New York. I have seen examples from 

 New England; Toronto, Ont. ; and Columbia, Mo. I have taken 

 a number of T. fraterculus Wh. at Lewiston, N. Y., and have seen 

 a series of eight from Berkeley- Hills, Cal.; Professor Aldrich re- 

 ports it from Mexico. 



The species of Thrypticus are minute flies of bright metallic 

 color with a concave area in front of the scutellum and with the 

 bristles and hairs of the thorax and abdomen yellow; the third 

 and fourth longitudinal veins are usually convergent at tip, but 

 sometimes parallel, and the hypopygium is flexed under the 

 abdomen, often reaching nearly to the thorax. 



The hypopygia of the males of those species I have examined 

 are very similar. There is a large capsule or outer part which is 

 covered with scales of pollen that are always inclined backward. 

 Its appendages are lamelliform with a pair of slender processes at 

 their base in most species (these seem to be lacking in ivillistoni). 

 There is also a central filament (the penis) which originates on 

 or near the base of the hypopygium and usually extends nearly 

 to the end of the lamellae; this filament is inclosed in a sheath which 

 is shorter and often so closely applied to it that the two appear 

 to form one piece. In the drawing of aurinotatus sp. nov. this 

 filament does not show as it was folded under the abdomen. 



