718 ASILID^. 



thorax and scutellum with abundant pubescence but with no bristles, the 

 abdomen with no bristles or even bristly hairs, the hind femora and tibiae 

 without any furry pubescence, and the wings with the anal cell closed. 



Lasiopogon has also only one British species, which has the face-beard 

 long strong and almost radiating on a large facial knob which occupies quite 

 the lower two-thirds of the face, the frons widening towards the vertex and 

 bearing numerous thin bristly hairs, the antennse almost as in Isopogon, 

 the thorax and scutellum bristly rather than hairy, the abdomen 

 pubescent but without bristles, the genitalia resembling those of the 

 Asilinoe, the hind femora and tibiae without any furry pubescence, and the 

 wings with the anal cell closed at the wingmargin. 



11. ISOPOGON. 



Isopogon Loew, Linn. Ent., ii., 492 (1847). 



Medium-sized hairy but bristle-less species of fairly stout 

 build, which have the thorax very much arched. 



Head very broad and short and by no means liigh, appearing depressed because 

 of the highly arched hump-backed thorax ; face wide, almost equal in width, and 

 so inconsiderably produced that it has no distinct facial knob ; face-beard covering 

 nearly all the face, and its hairs almost equally long and strong though less dense 

 on the upper part ; frons shorter than broad, scarcely widened though much sunk on 

 the upper part, without any antennal prominence but with the ocellar knob strongly 

 elevated, and bearing long dense bristly hairs on the orbits and on the ocellar knob. 

 Proboscis sloping forwards ; palpi short. Antennae approximated at the base ; the 

 two basal joints equally short, cup-shaped, and bearmg long bristly pubescence • 

 third joint elongate, narrow but slightly conical, with a long two-jointed apical 

 style which bears a minute bristle at its tip ; basal joint of the style short but 

 distinct, and the style altogether quite half as long as the third joint. 



Thorax short and very highly arched, hump-backed, densely hairy on all the disc 

 (/, brevirostris), or appearing almost bare anteriorly because of the shortness of the 

 pubescence (J. vitri-pennis), but with no trace of bristles ; pleurae almost bare except 

 for tomentum, but with a rather long soft silky pubescence on the upper part of the 

 mesopleuree and a tuft of long silky hairs on the metapleurse. Scutellum appearing 

 depressed because of the hump-backed thorax, bearing slight but not at all bristly 

 submarginal pubescence. 



Abdomen cylindrical, in the female pointed at the tip and with the segments 

 after the fifth forming a projecting flat ovipositor ; pubescence short and adpressed, 

 almost scabrous. Genitalia of the male small. 



Legs rather long though strong ; femora fairly thick, especially the hind pair • 

 front tibiae with a small curved apical claw occurring on the underside but twisted 

 a little posteriorly ; hind tarsi normal, or (/. brevirostris) remarkably elongate and 

 compressed to a knife-like edge in the male. Pulvilli and claws normal. 



Wings small at the base, almost wedge-shaped in outline ; first posterior cell not 

 ' contracted towards the wingmargin, fourth widely open, and the third more open 

 than the second or fourth ; fork of the cubital vein hardly bell-mouthed, longer 

 than its stem (measuring from the discal cross-vein) ; discal cross-vein after the 

 middle of the discal cell ; anal cell closed. Alar squamae narrow ; thoracal pair 

 practically absent. 



This genus appears to prefer hilly or mountain districts or at any rate 

 dry localities. It is allied to Lasiopogon in shape and venation but is very 

 easily distinguished by the presence of the hook at the tip of the front 

 tibiae, by the absence of any bristles on the thorax or scutellum, and by 

 the genitalia. The metamorphoses are unknown. 



