282 Orthorrhapha brachyceia. 



Length 1,3—2 mm. 



Ch. arenaria is probably common at our sea-shores, it has hitlierto 

 been taken at Tisvilde and on Lanc^eland at Lohals on ^ii — ^'^ii 1909 



Fig. 129. Wing of Ch. arenaria. 



(the author); it was present in great numbers together with the tiiree 

 preceding species. It is especially found running in the sea-weed on 

 the shore among which it slips swiftly, and it seems never to fly, for 

 which, I think, the wings are not sufficiently developed. 



Geographical distribution: — Scandinavia, Denmark and England; 

 it goes towards the north to northern Sweden but it is not known 

 south of Denmark and England. 



5. Ch. incana Walk. 

 1851. Walk. Ins. Brit. I, 138, 3. — 1903. Kat. palaarkt. Dipt. II, 278. 



Male. Frons and vertex grey ; epistoma and palpi whitish grey. 

 Occiput grey, only with short hairs, but without bristles. Antennæ 

 blackish or brownish, arista short. Thorax light grey, the disc clothed 

 with short, white hairs, which are divided by two bare stripes into 

 biserial acrostichal hairs and dorsocentral hairs, which latter are fused 

 with the hairs on the sides. There is one white notopleural bristle, 

 but I could detect no other bristles. Scutellum without bristles. 

 Pleura light grey, above the middle coxæ a more or less distinct, 

 very small, black, polished spot. Abdomen light grey, venter of the 

 same colour; some small white hairs are seen only at the sides. Legs 

 blackish, a little greyish pruinose; the knees more or less reddish; 

 generally the hind tibiæ and especially the metatarsi pale. The front 

 femora a little thickened. The legs are short-haired ; the anterior 

 femora with fme, short hairs below; the front tibiæ with a pair of 

 ventral subapical bristles, the middle tibiæ with a pair of bristles 

 near the apex; the hind tibiæ with a few bristles at the apex on the 

 dorsal and anterior side. The wings somewhat milk-white. Veins 

 pale brown. Halteres whitish. 



Female. Quite similar to the male; abdomen pointed. 



Length 1,2 — 1,6 mm. 



