398 Orthorrhapha brachycera. 



or slightly concave space. Acrostichalj bristles absent; there are six 

 dorsocentral bristles, further a humeral bristle, a posthumeral, two 

 notopleural, a præsutural, only two supraalar, and a postalar bristle; 

 there are only few, small hairs on the front part of the disc. Pro- 

 pleura have small hairs. Scutellum with two marginal bristles, and 

 at each side a very small hair. Abdomen compressed; in the male 

 there are five visible dorsal segments, the first shorter than the 

 following; as far as I could see there are four visible ventral seg- 

 ments, the others being folded up. The hypopygium lies exposed at 

 the end of abdomen, directed downwards and forwards; the eighth 

 segment is rather large, with some (2) bristles; there seem to be 

 distinct ventral lobes with small spines at the apex, and there are 

 linear outer lamellæ, with long hairs; they are not united, but quite 

 free. In the female there ai-e five visible abdominal segments, the 

 last somewhat long, and the abdomen terminates with a small ovi- 

 positor with longish hairs, and some small spines above at the apex. 

 The abdominal segments have short hindmarginal bristles, somewhat 

 longer on the firsl segment. Legs slender and somewhat long; hind 

 metatarsus of the length of the second joint, without bristles; in the 

 male the front femora are slightly thickened, and these and the tibiæ 

 armed with bristles below, and likewise the middle femora; the 

 posterior coxæ have each a bristle; femora without preapical bristles; 

 middle tibiæ with about two antero-dorsal, two postero-dorsal bristles, 

 and one or two small ventral bristles; posterior tibiæ with small 

 apical or preapical bristles. There are two small claws and pulvilli, 

 and a narrow, linear empodium with bristles below. Wings with the 

 mediastinal vein terminating in the subcostal vein; the discai vein 

 almost straight, parallel with the cubital vein; posterior cross-vein 

 about in the middle; anal vein weak and short. Axillary lobe somewhat 

 developed. The discai vein has a little convexity somewhat behind 

 the posterior cross-vein. Squamulæ with a small angulary lobe and 

 a long fringe; the inner part of squamulæ with short hairs. 



The developmental stages are not known. 



Of the genus only one palæarctic species is known, also occurring 

 in Denmark. 



1. A. flaviventris Meig. 



1824. Meig. Syst. Beschr. IV, 58, 28, et 1830. VI, 363 (Porphijrops\ 

 et 1838. VII, 155 (Medeterus). - 1862. Schin. F. A. I, 191. - 1903. KaL 

 palåarkt. Dipt. II, 350, 



Male. Vertex and frons blackish, dark grey pruinose. Eyes 

 touching below the antennæ, the epistoma only visible below, white. 



