280 Orthorihapha brachycera. 



It was several times taken in copula. This species occurs both on 

 the sea-shore and on horders of fresii water, 



Geographical distribution: — The species is hitherto known from 

 Scandinavia, England and Denmark; it goes towards the north to 

 middle Sweden. Zetterstedt also records the species both from sea- 

 shores and from the horders of streams and lakes, e. g. at Wettern. 



3, Ch. difficilis n. sp. 



This species resembles cursitans to so high a degree that I shall 

 only give the differences: 



Male. Occiput with only two bristles above, The acrostichal 

 bristles are more regularly biserial. A humeral bristle, some noto- 

 pleural, a supraalar and a postalar bristle are present, but I could 

 detect no posthumeral bristle. The exterior genitalia are smaller, 

 narrower than the last abdominal segment, and greyish pruinose; 

 they terminate with an upwards curved, black, shining process, which 

 is dilated and spoon-shaped at the apex. The legs black or reddish 

 brown, sometimes still paler, somewhat shining, not pruinose; the 

 middle tibiæ vi^ith a pair of bristles on the dorsal side and one on the 

 anterior side. The hind metatarsi not much longer than the second 



Fig. 128. Wing of Ch. difficilis. 



joint. Wings a little greyish or brownish, a space, bordered behind 

 by an oblique line stretching from the base of the cubital vein to the 

 end of the subcostal vein and belovv by the cubital vein, is distinctly 

 brown; the radial vein terminates in the middle between the ends of 

 the subcostal and the cubital vein, at the same distance from each. 



Female. Similar to the male; abdomen pointed. 



Length 1,8 — 2,4 mm. 



This species resembles cursitans very much, but is distinguished 

 with certainty by the shining legs, the bristles on the middle tibiæ 

 and especially by the direction of the radial vein; in the male also 

 the genitalia are characteristically different. I was in doubt which of 

 the two species, the present or the foregoing, was in reality cursitans 

 Zett., but as Zetterstedt mentions expressly the grev legs, I think 



