220 Orthorrhapha brachycera. 



closing the discai cell apically are brownish seamed, so that the wing 

 shows three more or less distinct, brownish spots; anal vein very 

 weak. No stigma. Halteres brown. 



Fig. 90. Wing of Cl. stagnalis. 



Female. Similar to the male in all respects, except the differences 

 in the exterior genitalia. 



Length 3,5—4,2 mm. 



Cl. stagnalis seems to be somewhat rare in Denmark, and not 

 many specimens have been caught, all in Jutland; at Silkeborg, Hald 

 Sø (the author), Struer (H. J. Hansen) and Tinbæk Mølle at Linden- 

 borg Aa (J. P. Kryger); the dates are '-^^/c to August. It occurs near 

 or over water, at Hald Sø I took it on the humid border and on the 

 surface just at the border. 



Geographical distribution: — Europe down into Italy and Spain. 

 It goes far towards the north, in Scandinavia to the northernmost 

 parts, and it has been caught on the Faroe-Islands and in Greenland; 

 in the latter I took it running on the surface of shallow water pools 

 in somewhat great number. 



3. Cl. Wesmaelii Macq. 



1835. Macq. Suit. å Buff. II, 656, 1, Tab. XXIV, fig. 17 {Paramesia). 

 — 1838. Meig. Syst. Beschr. VII, 79, 3 {Brachystoma). — 1842. Zett. Dipt. 

 Scand. I, 364, 6, p.p. (Brachystoma). — 1858. Loew, Wien. entom. Monatschr. 

 II, 257, 11. - 1862. Schin. F. A. I, 85. — 1881. Mik, Verh. zool. bot. 

 Geseli. Wien, XXXI, 326. — 1903. Kat. palåarkt. Dipt. II, 264. 



Male. Frons and vertex olive-brown; epistoma silvery white; 

 palpi blackish. Occiput grey, above with black bristles, below with 

 whitish hairs. Antennæ black or brownish black. Thorax olive-brown, 

 with two longitudinal, darker brown stripes, abbreviated behind ; the 

 space between the stripes greyish brown. The disc has five long, 

 black dorsocentral bristles in each row, but no acrostichal bristles. 

 Further a humeral bristle, a posthumeral, two notopleural, a supraalar 

 and a postalar bristle, all long, black. Scutellum with two black 

 marginal bristles. Pleura light bluish grey, metapleura brownish, with 



