268 NORTH AMERICAN DIPTERA 



Family Pyrgotidae 



Elongate flies of moderate size, tlie ocelli absent in the North Amer- 

 ican genera, present only in Teretnira Bigot of the American forms; 

 wings long, the legs somewhat elongate. 



Head large, the front more or less produced, without frontal bris- 

 tles; ocelli absent (present in only one American genus); checks wide; 

 proboscis thick, the labella? well developed; pal])i large, flattened, or 

 the proboscis narrow and short without labella? and the palpi narrow; 

 antenna- short to moderately long-, the second segment without a dorsal 

 excision, the third usually larger than the second, rarely minute. Legs 

 moderately long. Wings long; auxiliary vein long, ending free or in 

 the costa; apical cell widely open, not narrowed apically: anal cell 

 usually triangular a])ically. Abdomen long, sometimes elavate in the 

 males; female genitalia large, more or less cylindrical. 



Species of the genus Pijrgota are parasitic in the larval stage on 

 June beetles (Scarabaeida') and the flies are sometimes common in the 

 vicinity of badly infested fields. I suspect that PijrgoteJla chagnoni 

 Johnson is parasitic on species of DicheJonyx but my suspicion is 

 based merely upon the fact that I have observed this species commonly 

 in an open woods where the adult beetles were very common. The flies 

 apparently are most active on dark days, in the evening or at night 

 and they frequently are attracted to light. They are nocturnal and P. 

 undata Wiedemann has been observed ovipositing on adult June beetles 

 during flight. The flies select the soft part of the abdomen beneath 

 the opened elytra in order to lay their eggs and the beetles have been 

 observed on the ground making a loud noise as they struggled to escape 

 the fly. 



The exact limits of this family have not been definitely determined, 

 and it is not certain that the species possessing ocelli should be retained 

 in the family. Nothing of a definite nature is known of the immature 

 stages of any of the American genera other than Pjirgota. There are 

 two North American genera and three from South America that have 

 been assigned to the familv. 



