Aphiochaeta. 271 



backwards, on the sixth segment they are somewhat long at the hind 

 margin and also longish at the sides; venter with distinct hairs at 

 the hind margins of the segments. Hypopygium somewhat large, 

 greyish black, on each side there are aboiit six bristles in a nearly 

 vertical, but above backwards curved row, they are directed down- 

 wards (fig. 85); anal tube dusky yellow to blackish with the apex 

 yellow; ventral plate generally protruding downwards, it is narrow, 

 broadened towards the end and somewhat spoon-shaped, dusky 

 yellow; a complicated, black subanal body as a rule protruding. 

 Legs yellowish brown to brownish black, front tibiæ and tarsi a 



Fig. 86. Wing of A. pleuralis ^ . 



little paler; hind femora with short hairs below; hind tibial bristles 

 of medium size, the dorsal hair-seam deflected anteriorly from the 

 middle downwards. Wings a little yellowish brown tinged, veins 

 brown or pale brown; costa reaching to or beyond the middle, 1 

 slightly or somewhat longer than 2 and from a little shorter than 

 to about equal to 2+3; costal cilia full long; fourth vein a little 

 curved in the basal part, for the rest very slightly curved. Halteres 

 yellow. 



Female. Similar; antennæ a little smaller; the first costal divi- 

 sion may be relatively longer; fourth vein generally a little more 

 strongly curved in the basal part. 



Length 1,4 — 2,5 mm. 



Wood says that the fore tarsi are somewhat stout in the female 

 and stouter than in the male; this I am not able to see. — Specimens 

 of the smallest size are of rather rare occurrence, such small specimens 

 may have the mesopleural bristles weaker and the longer bristle 

 rather small. 



This well characterised species is common in Denmark all over 

 the country; my dates are ^°/i — ^"/u in 1916 to 1921; I have taken 

 it in copula on ^Vs and ^"/g. 



