188 Orthorrhapha brachycera. 



of bristles above, and one ventral bristle; hind tibiæ with two rows 

 above and with a few, smaller ventral bristles. Wings somewhat 

 brownish tinged, most towards the anterior margin; they are a little 

 broader than in celer as the anterior margin is curved a little out- 



Fig. 55. Wing of H. brevicornis cf. 



wards; veins black, costa thickened as in cele?-; discai vein with a 

 very slight bend, a little converging towards the cubital vein; axillary 

 lobe a little larger than in celer. Squamulæ yellow, with a black 

 fringe. Halteres yellow. 



Female. Epistoma broad. Antennæ about as in the male. Wings 

 more tinged and with the thickening of costa present, but thinner 

 than in the male. Hind metatarsi generally quite black. 



Length 3 — 3,8 mm. 



H. brevicornis is common in Denmark; Charlottenlund, Ordrup 

 Mose, Ermelund, Dyrehaven, Bøllemosen, Geel Skov and Ørholm; it 

 has thus hitherto only been taken on Sealand. My dates are ^^le—^ls. 

 It occurs in woods at the horders of water and on water piants in 

 ditches, often in great number; though this species and celer occur 

 in similar localities I have however never taken them together. — 

 The species was originally founded on Danish specimens. 



Geographical distribution: — Northern and middle Europe down 

 into Styria and Hungary; towards the north to southern Sweden. 



Remarks: H. celer and brevicornis may in the males easily be 

 distinguished by the colour of the lamellæ of the hypopygium; also 

 celer has longer antennæ with a more distinctly haired arista, and a 

 broader epistoma; the females are very similar, they may on close 

 examination always be known as belonging to one of the two species 

 by the slight thickening of the costa near the base, but they are diffi- 

 cult to distinguish from one another; brevicornis may be known from 

 celer by the somewhat broader wings, the costal margin being less 

 straight than in celer; further the hind tibiæ are often a little brownish 

 at the apex, and the hind metatarsus is generally quite black, while 

 in celer it is always more or less yellow. 



