FAMILY ASILID.K — TIIK ASSASSIN FLIES 169 



Many of the Asilids resemble bees and are quite powerful. Tliey 

 devour insects of all kinds, catehinii' them (hiring flight, and bees form 

 the princi])al article of diet of some species although the variety of 

 food is usually limited only by the intended victim's ability to escape. 

 The prey is pierced by the powerful proboscis and the juices sucked 

 out, the digestion taking place by the injection into the victim of a 

 powerful "enzyme" which breaks down the muscular tissue. The col- 

 lector should be careful in handling the larger species as they not 

 infrequently bite, resulting in a painful, if not serious, wound. 



The family is a large and popular one and includes many fine 

 species. For the most part the classification is simple but in some 

 genera it is difficult to separate the species by means of the available 

 literature. There has been no monograph of the Nearetic species 

 although Back* has dealt with about half the family. However, since 

 the appearance of his contribution very many additional species have 

 been described. Otherwise the literature is scattered although not diffi- 

 cult to obtain. 



In tlie key will be found many references to keys to species which 

 should ])rove very lielpful in tracing out the species. I have not fol- 

 lowed the practice of recognizing subfamilies as the characters previ- 

 ously used obviously separate related genera and some genera are 

 difficult to place where the system is followed. For Cuban species 

 see Bromley "The Asilicte of Cuba,'' (Ann. Ent. Soc. Amer., xxii, 

 pp. 272-294) ; also Texas AsilidtT by the same author. f 



KEY TO GENERA 



1. Anterior tibiae with a terminal, sharply curved, ventral spur 2 



Anterior tibiae with only straight or gently curving apical bristles. ... 17 



2. Marginal cell closed and petiolate (121) 3 



Marginal cell open 4 



3. Face bare except for a very few hairs on the oral margin (121, 122). 



Doryclus Jaennicke 

 Face with strong hairs and many on the oral margin (21, 41). 



Pseudorus Walker 



4. Middle of mesonotum raised and bearing a crest of long, dense hairs 



(50, 86) JComantella Curran 



Mesonotum never with crest of dense hair 5 



5. Antennae with distinct, two-segmented apical style 13 



Antennae either with a short, broad, one-segmented style bearing a 



spine in the depression, without style, or excised and bearing a spine 

 above 6 



* 1909, Tr. Amer. Ent. Soc. xxxv, pp. 137-400, plates IT-XII. 

 t Bromley, 1934, Ann. Ent. Soc. Amer., xxvii, pp. 74-114. 

 J Curran, 1926. Can. Ent., Iviii, p. 311. 



