27 
costa 0,42 of the wing-length, costal divisions proportionately about 
as 11—4—2; second vein rather thick, the fork short and the 
outer branch a little angulated; costal cilia long but not very long; 
fourth vein evenly and only slightly curved, beginning just below 
the base of the fork, slightly s-like at the base and not or not 
distinctly recurved at the end. Halteres black. — Female. Similar 
but the hairs below the hind femora not so long as in the male 
and the pale hind margins on abdomen broader and more distinet. 
Length 1 , 5 — 1,8 mm. 
Bogø south of Sealand 19 A — 25 /7 1917, Ry in Jutland 22 /7 — 29 /7 
1918 (the author); five males and one female. 
31. A. pallidizona n. sp. J $. 
A species near halterata Wood but with a longer costa, a cur- 
ious colouring and only one bristle on the hypopygium. 
Male. Frons very broad, 1 Vs times as broad as long or still 
broader, grey or blackish grey; bristles strong, inner bristle of 
lower row below the outer and nearer to it than to the upper 
supraantennal; supraantennal bristles not large, unequal, the lower 
scarcely half as large as the upper; the upper supraantennals a 
little more approximated than the inner bristles of the middle row, 
the lower ones not or slightly more approximated than the upper. 
Antennæ above ordinary size, reddish brown, arista apparently 
nearly nude. Palpi yellow or pale yellow, somewhat narrow, the 
three apical bristles well developed, the others shorter. Thorax 
varying from blackish brown to red, pleura brown or red, palest 
anteriorly; mesopleura bare. Scutellum with two bristles. Abdomen 
black, often with very narrow paler hind margins to the segments; 
the basal half of the first segment, the fifth segment and a tri- 
angular basal spot on the sixth yellow or red; these colours may 
be rather obscured but are allways visible to some degree; venter 
yellow, the hinder part of it without the dense bristles which are 
found here in halterata. Hypopygium somewhat small, black or 
greyish black, with one conspicuous bristle below on each side; 
ventral plate rectangular, whitish; anal tube short, yellow. Legs 
yellow or pale yellow, hind femora brownish just at apex; below 
the basal part of hind femora some sparse, only slightly longish 
