Asilidae. 45 



latter species also have scutellar marginal bristles. Metapleura have 

 long bristles, hypopleura shorter hairs. Metathorax rather distinct, there 

 is a considerable metasternum, the space between it and the hind 

 coxæ membranous. Abdonien consists of eight segments, which are 

 however not all visible; the first dorsal segment is a little shorter than 

 the following; the first ventral segment is very short. In the male 

 at most seven segments are visible, the eighth segment is very small 

 and completely hidden; it is formed of a small ventral plate and a 

 very short dorsal annulus. The male genitalia are very large; they 

 consist, so far as I have been able to examine, of an upper pair of 

 forceps with generally rather broad arms, but othervvise of different shape 

 in the different species, and of a lower pair lying more inwards and 

 very complicated with two-branched arms, but likewise of different 

 shape in the different species ; the upper and lower forceps are strongly 

 connected, so that it would perhaps be correct only to speak of one 

 pair of forceps. There is a large, arched ventral lamella, reaching to 

 the apex of the upper forceps. In the interior is the penis with a thick 

 base and an upwardly curved, three-pointed apex, There was no 

 dorsal median lamella to be seen, but the ventral lamella has at the 

 apex a pair of small styles, sitting on a basal piece which is articu- 

 lated to the ventral lamella. In the female eight segments are visible; 

 the eighth ventral segment has from the hind margin a shovel-shaped 

 prolongation; the ninth segment forms a shorter or longer ovipositor 

 terminating in a pair of small styles. Legs somewhat strong, in some 

 .species stronger than in others and with club-shaped hind femora; 

 they are more or less strongly haired, in some species also with 

 stronger spine-like bristles. All tibiæ have apical spurs; the tarsi have 

 strong bristles, The front tibiæ have a dense pubescence on the 

 ventral side, and the hind tibiæ a similar pubescence at the apex; 

 the tarsi are densely pubescent below, The claws are strong; there 

 are two pulvilli and a somewhat claw-shaped empodium. Wings with 

 the subcostal cell closed a little before the margin, the cubital vein 

 branched; between the discai cell and the upper branch of the posti- 

 cal vein a postical cross vein; five postei'ior cells, the fourth closed 

 somewhat before the margin; anal cell closed, Alula large; alar 

 squamula small, hairy at the margin, When the wings in rest are 

 lying parallel over the abdomen, the squamulæ point outwards in a 

 somewhat process-like way, 



The larva (L. yilva) is cylindrical, thickest at the front end, whitish, 

 with distinctly marked segments; it is finely striated longitudinally, 

 It consists of thirteen segments including the head and when the seg- 

 ment-like part bearing the posterior spiracles is counted as a segment. 



