128 Orthorrhapha brachycera. 



the anterior margin; veins brown; costa at the base witli black 

 spinules in the margin and yellow haired above. Squamulæ light 

 brownish with a yellow fringe at the margin. Halteres brownish 

 with the knob white or yellowish white. 



Female. Agreeing with the male but the frons broad; the legs 

 generally lighter, 



Length 4 — 6,5 mm. 



Remarks: The bristles at the hind margin of the abdominal 

 segments are generally described as black; in all the Danish specimens 

 I have seen they are nearly always yellow to light brownish. 



S. sulphureus is common in Denmark in suitable localities; Tis- 

 vilde, Rørvig; on Funen at Faaborg; in Jutland at VillebøUe north of 

 Ribe, Silkeborg, Kandestederne south of Skagen and Skagen. My dates 

 are ^''/e to the first half of August. It occurs in sandy districts and 

 especially on heaths, often in great numbers. I generally found it on 

 the heaths at piaces where the Galluna was scattered, with the sand 

 somewhat open and covered by Lichens; it flies very dexterously and 

 is not easily caught. As already noticed by Zeller (Isis 1840, 14, 16) 

 the fly produces a faint humming when flying. 



Geographical distribution: — Europe down into Italy; towards 

 the north to middle Scandinavia; also in parts of Asia and in the 

 northern Africa. 



6. Plithiria Meig. 

 Species of small size and of greyish or blackish colour, moderately 

 hairy; sometimes the females have yellow markings. Head somewhat 

 broader than thorax and broader than high, slightly arched behind; 

 frons and face more or less protruding. Eyes touching in the male, 

 broadly separated in the female. Antennæ inserted near to each 

 other in the middle on the protruding face. Jowls somewhat de- 



Fig. 43. Anlenna of P. puUcaria. X 90. 



scending below the eyes, Antennæ three-jointed, the two basal joints 

 short, cylindrical, the third long, somewhat compressed, at the apex 

 terminating in a thinner, short, styliform part, and below this part is 



