Aphiochaeta. 263 



Mesopleura bristly, witli one bristle longer than tlie others, but 

 not specially strong. Abdomen black, dull, with very short hairs, 

 slightly longer at the hind corners of the segments ; at the hind margin 

 of sixth segment the hairs are a little longer or sometimes rather long. 

 Hypopygium of medium size, symmetricai, with some small bristles 

 on each side at the base and hairy above on the hind part; anal tube 

 of medium size, brownish with yellow apex; there is a yellow or dusky 

 ventral plate, rounded at the end, flap-like. Legs yellowish brown 

 to dark brown, the front legs yellowish; hind femora a little broad, 

 with the hairs below the basal half short or a little longish; hind 

 tibial bristles distinct, but delicate, sometimes somewhat stronger. 

 Wings greyish or greyish brown tinged, veins brown; thin veins some- 

 what strong, only the seventh weaker and more colourless; costa 

 reaching to the middle, 1 about double 2 and longer than 2 + 3; 

 costal cilia short; fork longish and somewhat acute; fourth vein 

 evenly curved in the whole length, only slightly more at the base. 

 Halteres black, sometimes yellow. 



Female. Similar, antennæ very slightly smaller. 



Length 1,5 — 2 mm. 



As seen this species varies with black and yellow halteres, and this 

 is followed by variation in some other characters, for the specimens 

 with yellow halteres have the bristles at the hind margin of sixth 

 segment, on the hypopygium, the hind tibial bristles and sometimes 

 also the bristles on the palpi stronger than the specimens with black 

 halteres; I follow, however, Schmitz (1. c. 1919) in regarding them 

 as one species as they in other respects are quite agreeing and as 

 f. inst. the bristles on the palpi may be short in specimens with yellow 

 halteres and longer in such with black halteres. — I have compared 

 my specimens with Schmitz' types, both specimens with yellow and 

 with black halteres. 



A. limburgensis does not seem to be common in Denmark; Holte, 

 Suserup Skov at Sorø, Bogø south of Sealand, Marienlyst on Falster 

 and in Jutland at Ry (Th. Mortensen, the autlior) and at Frederiks- 

 havn (H. J. Hansen); the dates are V? — ^V? in 1917 to 1921, but 

 the specimens from Frederikshavn was taken in 1881, the first time 

 the species was taken in Denmark. We have in all thirteen specimens 

 of which only two, both males from Suserup Skov, have yellow 

 halteres. 



Geographical distribution: — Besides in Denmark the species 

 occurs in Holland and Germany. 



