Leucostoma. 121 



13. Leucostoma Meig. 



Small black species. Head broader than thorax, nearly flat 

 behind and very slightly pufled out below, higher than long. Frons 

 in male somewhat narrow above, in female broader, not protruding. 

 Jowls narrow. Outwards directed ocellar and in male weak inner 

 vertical bristles, in female the latter strong and also outer vertical 

 and two orbital bristles present. Behind postocular bristles black 

 hairs. Frontal bristles reaching to or just below insertion of antennæ,. 

 in female the uppermost directed outwards. Cheeks bare. Vibrissæ 

 not ascending, the large vibrissa a little above the lower margin of 

 epistoma. Epistoma not retreating, nearly flat. Proboscis of medium 

 length. Palpi somewhat small. Antennæ inserted at the middle of 

 the eye, short, third joint almost not longer than second; arista 

 thickened in basal third or nearly half, pubescent, second joint 

 short. Thorax rectangular; three postsutural dorsocentrals, one 

 pair of præsutural and one of præscutellar acrostichals. Scutellum 

 with three marginal bristles on each side. Two sternopleural bristles. 

 Above on pteropleura a bristle and some hairs. Abdomen elongate,. 

 somewhat cylindrical, a little narrowed in front and behind; excava- 

 tion on second segment only present at base. Abdomen has only 

 marginal bristles, on second segment a pair. Genitalia in male small. 

 In female abdomen ending with a forceps. Legs a little slender; 

 ventral bristle on middle tibiæ present in both sexes; last tarsal 

 joint in male somewhat long, and claws and pulvilli a little elongated. 

 Wings with the first posterior cell long-petiolate, the peduncle ending 

 before apex of wing; angle on discai vein a little obtuse; anal vein 

 short. No costal spine; a single small bristle at the base of cubital vein. 



The species probably belong to Pantel's group 9. 



Of the genus up towards ten European species are recorded; 

 one occurs in Denmark. 



1. L. simplex Fall. 



1820. Fall. Dipt. Suec. Muse. 8, 10 {Ocyptera). — 1824. Meig. Syst. Beschr. 

 IV, 289, 89 (Tachina) et 1838. VIII, 212, 4. — 1844. Zett. Dipt. Scand. III, 

 1235, 5. — 1862. Schin. F. A. I, 543. — 1889. B. B. Denksehr. Akad. Wiss. 

 Wien, LVI, 143, Tab. XI, Fig. 292 (Psalida). — 1894. Pand. Rev. Entom. 

 XIII, 80, 7 {ClairvilUa). — 1907. Kat. palåarkt. Dipt. III, 328. — 1924. Stein, 

 Arch. f. Naturgesch. 90, 6, 245, 2. 



Male. Frons about half as broad as the eye, not protruding. 

 Orbits and face silvery; frontal stripe velvet black. Frontal bristles. 



