12. LASIOPOGON 723 



12. LASIOPOGON. 



Lasiopogon Loew, Linn. Ent., ii., 508 (1847). 



Middle-sized moderately elongate rather bristly flies of 

 blackish grey or dark yellowish grey colour with greyish white 

 hindmargins to the abdominal segments. 



Head not widei- than the thorax and not very short : face narrowest near the 

 antenn;\! but distinctly widening downwards ; face-knob large, occupying fully the 

 lower two-thirds of the face and clothed all over with a long strong-haired outstand- 

 ing or rather drooping face-beard which leaves only the upper part of the face and 

 just the sides bare ; a brilliantly shining bare black space separates the side-cheeks 

 from the jowls ; lower part of the back of the head wide even if not truly inflated 

 and bearing abundant long silky pubescence, but the upper part shallower and 

 bearing a rather abundant postocular festoon of long black bristles which extend 

 well round the upper eye-angles and are sharply bent over forwards soon after their 

 base ; when seen from above the upper part of the back of the head behind the 

 festoon bears a_ few rather long thin suberect hairs ; frons broad, narrowest near the 

 antennie but widening upwards (because of the widening orbits and the rounded-otf 

 upper eye-angles) until it is twice as wide at the vertex, and it is impressed with 

 three rather deep parallel longitudinal furrows, of which the outer ones extend 

 from the occiput to the antennte and the middle one begins just in front of the 

 lowest ocellus ; the orbits and the spaces between the furrows bear numerous thin 

 black bristles, but the upper middle part of the frons and the middle furrow are 

 bare ; ocellar knob not much elevated but bearing some long bristly hairs ; collar 

 only slightly prominent, pubescent but without bristles. Proboscis prominent 

 and sloping downwards, without much pubescence 'about the tip but with long 

 pubescence beneath near the base ; palpi short and narrow, apparently one-jointed 

 and bare or with only very slight porrected bristly hairs. Eyes very much flattened 

 on the front part, and the facets there considerably enlarged. Antennae approxi- 

 mated at the base ; the two basal joints short and bearing rather long thin bristles ; 

 second joint stouter and a little shorter than the basal one ; third joint strap-shaped, 

 of medium length, longer than the basal two together, and with' a fairly long style 

 (quite a third the length of the third joint) which has a minute pointed bristle at 

 its end; one or two rather depressed but not very minute bristles occur on the 

 dorsum of the third antennal joint between the middle and the tip in all the species 

 I have seen. 



Thorax very flatly arched, moderately bristly. Bristles consisting of about three 

 (2-4 or even 5) prtesutural, about three (3-6) supra-alar, and one or two postalar, 

 while the dorso-central rows are evidenced by about five rather well defined post- 

 sutural and about five less well defined prsesutural bristles, but these latter ones die 

 out on the front quarter of the disc ; in addition to these bristles short bristly hairs 

 occur almost all oyer the disc, though rather sparsely on the back part. JPleurse with 

 a slight row of bristles near the hindmargin of the mesopleurse, and with a long row 

 (hardly a fan) of about ten (7-10) long strong bristly hairs near the hindmargin of 

 the metapleuraj, while the upper part of the sternopleura^ bears a little thin 

 pubescence ; hypopleairaj quite bare of pubescence or bristles. Scutellum flat and 

 almost bare on the disc, but with about ten long thin upturned marginal bristles 

 and several shorter thin hairs. 



Abdomen flatly cylindrical, moderately_ hairy but without bristles, black with 

 conspicuous pale grey bands across the hindmargins of the segments • segments 

 gradually decreasing in length after the second one. Genitalia shining, m the male 

 rather large and with the eighth aljdominal segment forming the dorsal base as it is 

 considerably produced on each side into a somewhat triangular lobe ; claspers large, 

 resembling those of the Asi/imr, and bearing bristly hairs ; in the female the genitalia 

 after or under the flattened eighth segment are small and concealed but show an 

 obvious incomplete terminal circlet of about sixteen stout short bristles. 



Legs rather long, with the hind femora rather the longest ; basal joint of the 

 anterior tarsi only a little longer than the next, and of the hind tarsi not twice as 



