DIPTERA, 



473 



Professor Williston describes about three hundred species 

 from this region.^ 



Family PlPUNCULlD^ (Pip-un-cu'li-dae). 



The Big-eyed Flies. 



This family is represented in the United States by a 

 single genus, Pipuncuhis (Pi-pun'cu-lus). These are small flies, 

 with very large heads composed almost en- 

 tirely of eyes (Fig. 577). The head is nearly 

 spherical, and broader than the thorax. The 

 abdomen is somewhat elongate with the sides 

 nearly parallel. The body is thinly clothed 

 with hair or nearly naked. The wings are 

 much longer than the abdomen, and when at 

 rest they lie parallel to each other upon it. 

 (Fig. 578) closely resembles that of some of the Conopidae. 

 Vein III is three-branched. The last branch of Vein III and 



i:i2+3 



Fig. 577. — Pipuji- 

 cuius. 



The venation 



V112-MX 



Fig. 578. — Wing of Pipunculus. 



the first branch of vein V approach each other at their tips. 

 Vein V3 coalesces with vein VII, for nearly its entire length. 

 Veins VII, and IX coalesce at their tips. Cells III and V 



are long. 



The flies hover in shady places. They are sometimes 

 found on flowers, and may be swept from low plants ; our 

 most common species measure about one eighth of an inch 

 in length, not including the wings. The larvae so far as 



known are parasitic upon bugs. 



* Bulletin of the U. S. National Museum, No. 31. 



