304 Orthorrhapha brachycera. 



SO that the apex is lylng sornewhat downwards ; the arista is apical or 

 siibapical, ' about as long as or a little longer than tlie antennæ; its 

 first joint is short; the basal antennal joint is bare above, the second 

 has bristles at the apex, the third is distinctly and somewhat strongly 

 hairy, and the arista short-hairy. Clypeus separated from epistoma 

 by a slight transverse ridge, it does not reach the lovver margin of 

 the eyes. Proboscis somewhat protruding, and only slightly larger in 

 the female than in the male. Thorax rectangular, a little arched 

 above, and it has a small, flat, slightly declining area behind, in front 

 of the scutellum. Acrostichal bristles small, distinctly biserial; there 

 are five dorsocentral bristles, a humeral, a posthumeral, two noto- 

 pleural, a præsutural, only two supraalar, and a postalar bristle. 

 Scutellum bare above, with two strong marginal bristles, and some- 

 times a small hair at each side; propleura with one prothoracic 

 bristle. Abdomen somewhat cylindrical, in the male it has five or 

 six visible dorsal segments according as the sixth segment is visible 

 (melanotrichus, non Danish) or hidden (cinereus); in flavicollis it is 

 visible, but very small; on the ventral side there are four developed 

 segments. The hypopygium is roundish; it is exposed, but not 

 pedunculated ; there seem to be ventral lobes of various shape; the 

 OLiter lamellæ are somewhat long, more or less lancet-shaped ; the 

 eighth segment has shorter or longer hairs. In the female the ab- 

 domen has six normal segments of about equal length, and it ter- 

 minales with a somewhat thick. ovipositor with small spines above ^. 

 There are dot-like impressions on some of the segments, at all events 

 in the female. The abdominal segments with very short hindmarginal 

 bristles. Legs somewhat slender, simple ; hind metatarsus shorter than 

 the second joint, without bristles; hind coxæ with a bristle on the 

 outer side; posterior femora with a preapical bristle; tibiæ with few 

 bristles, front tibiæ only with one above; middle tibiæ without ven- 

 tral bristles; othervvise the tibiæ wilh apical bristles, small or wanting 

 on the front tibiæ. There are two small claws, two pulvilli, and a 

 small, linear empodium with bristles below. Wings with the media- 

 stinal vein somewhat indistinct, terminating in the subcostal vein, the 

 discai vein straight, nearly parallel with the cubital vein; the posterior 

 cross-vein about in the middle; no anal vein, and also the lower 



^ The arista is generally termed siibapical, but in cinereus I find it apical. 



^ I have seen these spines distinctly in A. flavicollis; Loew says in his diagnosis 

 of Achalcus (Mon. of Dipt. of N, Am. II, 1864, 217) that there is no "coronet 

 of brislles", but this is nol correct. Also Mik says about A. melanotrichus 

 (Dipt. Unters. Jahresb. k. k. akad. Gyrnn. Wien, 1878, 20) with regard to the 

 ovipositor: "die Klappen .... nicht gedornelt". 



