ASILID^ 615 



central, and marginal scutellar bristles, while a continuation of the supra-alar 

 bristles out on to the disc appears to sometimes show several intra-alar 

 (Asilus) ; the dorso-central bristles form two rows only and are most developed 

 between the suture and the hindmargin, but sometimes dwindle in strength 

 towards the hindmargin and usually extend forwards until about half-way 

 between the suture and the foremargin. Pubescence of the thorax, other than the 

 macrochsetse, often very short but not unfrequently gradually developed into long 

 dense humble-bee-like clothing {Laphria^ etc.) or into short stubby bristles which 

 extend over most of the disc and usually become longer towards the hindmargin, and 

 in some cases this bristly pubescence becomes longer and may extend along at least 

 the middle stripe right up to the front {Dysmachtis, Lophonotus^ etc.) with some- 

 times a mane-like appearance. Pleurae never quite bare, though sometimes with only 

 just traces of the metapleural fan but more commonly with slight pubescence on 

 various parts and with the metapleural and hypopleural fans distinct and composed 

 of long more or less bristly hairs or even decided bristles (especially in the Asilince), 

 or in other species the pleurae may bear dense long pubescence in which all bristles 

 are lost (especially in the Laphrinm), and occasionally the meta]3leur^ and 

 hypopleurae are quite bare {Stenopogon). Scutellum ranging from being quite bare 

 {Leptocja^ter) to bearing slight or even dense pubescence without marginal bristles, 

 or with slight short pubescence on the disc and several long strong upturned 

 marginal bristles ; metanotum rather large but considerably overhung by the 

 scutellum when the latter is large. 



Abdomen usually elongate, composed (in most species) of eight segments irre- 

 spective of the genitalia, but the eighth segment sometimes entirely or partially 

 concealed (at least dorsally) in the male and commonly forming part of the 

 ovipositor in the female. Genitalia usually prominent and conspicuous in both 

 sexes, and in some species a circlet of bristles occurs at the end of the ovif)Ositor 

 similar to that in the Therevidce, etc. 



Legs powerful and rather long, but rarely very much elongated, often hairy, and 

 often beset with thorn-like bristles ; tibiae with a terminal circlet of spines, and 

 frequently (in the Dasypogonince) with a curious strong curved 

 thorn placed antero-ventrally and curving underneath the end 

 of the front tibiae ; tarsi usually broad and powerful, also armed 

 with a terminal circlet of spines at the tip of each of the four 

 basal joints, and almost always with one posterior bristle near 

 the base of the basal joint of the front tarsi, one anterior and 

 one posterior one near the base of the middle tarsi, and one 

 similar anterior one near the base of the hind tarsi, these four 

 bristles being probably brought together when grasping prey. 

 Pulvilli two, with a thin bristle-like empodium between them 

 (fig. 338), but exceptionally {Leptogaster, etc.) the pulvilli 

 entirely absent or only partially developed ; claws usually 

 poAverful and strongly curved. 



Wings usually rather long and narrow, when at rest lying fig. 338.— .4s««s era. 

 flat and overlapping on the abdomen. Venation always con- ironiformis $• 

 forming to one type in which but little variation occurs; (End of front tarsus.) 

 veins never pubescent nor bristly ; subcostal vein very long and in the Asilince 

 and Lajihrince receiving the radial vein before its tip, but in the Dasypo- 

 gonince not quite so long though still longer than in any other family except the 

 Apioceridce and Mydaicke ; pra^furca rather unusually long, starting before the 

 middle of the upper basal cell and far before the base of the discal cell ; cubital vein 

 with a long usually rather bell-mouthed fork which usually includes the wing-tip, 

 but sometimes the lower branch of the fork curves up enough to end at or before the 

 wing-tip (fig. 349) and sometimes the upper branch bends down to or below the 

 wing-tip while occasionally the lower branch bends down enough to join the upper 

 veinlet from the discal cell and thereby forms a closed first posterior cell (fig. 350), 

 and sometimes the upper branch of the cubital fork throws back a recurrent 

 veinlet (fig. 350) from near its base which may even extend completely back to the 

 radial vein (fig. 346) and thereby cause the existence of three submarginal cells ; 

 posterior cells almost invariably five (two American genera have only four), of which 

 the fourth is frequently closed through the third veinlet from the discal cell bending 

 down enough to meet the upper branch of the postical vein, while individual species 

 occur in which other posterior cells are closed ; anal cell either closed near the 



