DOLTCII()P<)l)n:).'E. 



some cases the males liave small snow-white spots in the tip 

 of the wing. Anal cell always very short. 



This family perhaps sur})asses any other natural group of 

 animals in the variety of sexual ornaments possessed by the 

 males. These are paraded before the females, as are similar 

 ornaments in the peacock and turkey-cock. See " Courtship 

 Among the Flies ", American Naturalist, Jan. '94, ]>. 36. 

 They may occur in almost au}^ external portion of the body. 

 In a carefiil examination of a large number of species, I have 

 never found any two in which they are identical. I am ac- 

 quainted with at least fifty different forms of tarsal modifica- 

 tion alone, every one of which is distinctive of its species. 

 Nevertheless some species seem to offer no noticeable sexual 

 differences beyond the presence of the hypopygium in the 

 male ; even this is in some cases but little visible. 



In adult life all are predaceous, capturing chiefly the 

 minuter soft bodied flies, which they enclose within their soft 

 lal)ella, while extracting the juices ; the larvas are, as far as 

 known, feeders on decaying vegetation. 



The following table is designed solely to enable beginners 

 to detei-mine the genera of their specimens : it does not, there- 

 fore indicate anything about tl;e natui'al relations of the gen- 

 era to each other. Tt4»-based on nuile specimens onlv-, since 

 otherwise it litust have included many oljscure and dilh cult 

 characters. 



TABLE OF GENEKA. 



1. Fourth longitiulinal vein with a widely (Uvcrgcnt fork on the front si(h' ; 



or if not, the head wider than the thorax, face, wide, and the front 



deejily exeavated (Fsil()])ina'). . .'■ -_" ^ ; . . . 2 



Foiirtli vein sinijjle or merely biolcen , front not exeavated. . . 6 



2. Fourth hmgitudinal vein not forked. . . Ai'Toitrm s Ahlrieli. 

 Fourth U)njiitudinal vein forked. .......•"> 



.'5. Tegular cilia hlaek, third longitudinal vein eurved gently back at tiji, 



seutelluni with four large bristles. . . . h'sii.oi'rs Meigen. 



'IVgular eilia jiale, third vein distinetly eurveil forward iit the fiji, seu- 



tellnin with two large and usually two small bristles. . . 4 



