Empididae. 281 



there can be no doubt, that the preceding species is cursitans; nor 

 does Zetterstedt mention the distinct brownish colour on the wings. 



Ch.difficUis seems to be as common in Denmark as cursitans; it 

 has hitherto only been taken on the sea-shore at Vemmetofte in June 

 1884 (H. J. Hansen), at Tisvilde and on Langeland at Lohals in 1909 

 on ^/t — ^^/t (the author). At Lohals it was as frequent as cursitans 

 and found running in company with this in quite the same way, and 

 it was also taken in copula. 



Geographical distribution : — Besides in Denmark the species also 

 occurs in England according to specimens sent to me from Mr. 

 Verrall. 



4. Ch. arenaria Hal. 



1833. Hal. Entom. Mag. I, 161 (Tachijpeza) . — 1835. Walk. Entom. 

 Mag. III, 180 {Tachypeza). — 1903. Kai. palaarkt. Dipt. II, 278. — Tachy- 

 peza bt-evipennis : 1838, Zett. Ins. Lapp. 548, 8, et 1842. Dipt. Scand. I, 

 323, 13, et 1859. XIII, 4996, 13. 



Male. Frons and vertex grey; epistoma and palpi of the same 

 colour. Occiput likewise grey, with four long, black bristles above 

 and with shorter hairs downwards. Antennæ blackish brown or brown. 

 Thorax grey, with short, biserial acrostichal bristles, and longer, 

 uniserial dorsocentral bristles; the sides of the disc with short hairs. 

 Further a humeral bristle, some notopleural, a small supraalar and a 

 postalar bristle. All the hairs and bristles black. Scutellum with 

 two black marginal bristles. Pleura grey pruinose, above the middle 

 coxæ a small, black, shining, polished spot. Abdomen black, slightly 

 greyish pruinose, with short, dark hairs. Venter of the same colour, 

 with a little longer hairs. Exterior genitalia not large. Legs more 

 or less dark to almost blackish ferruginous, somewhat shining; the 

 front femora somewhat thickened. The femora with short, fine hairs 

 below, and the hind femora with a few bristles at the apex below; 

 all femora with a bristle at the apex on the anterior side; the anterior 

 tibiæ short-haired, the front tibiæ with a pair, the middle tibiæ with 

 one ventral subapical bristle; the hind tibiæ with bristles on the 

 dorsal, anterior and aiitero-ventral side in the apical half. The hairs 

 dark brownish or blackish, the bristles black. The wings small and 

 short, not longer than abdomen, somewhat brownish, especially to- 

 wards the anterior margin, the base of the subcostal cell clearer (as 

 in difficilis). The veins brown, the discai vein pale from the base to 

 considerably beyond the postical cross-vein. Halteres brown or blackish 

 brown, the peduncle paler. ' 



Female. Similar to the male; abdomen longer and pointed. 



