Empididae. 313 



near Silkeborg; my dates are '^^Ig — ^/s. It occurs in the outskirts of 

 woods, and on shaded piaces in woods on bushes. 



Geographichal distribution: — Europe down into Italy; towards 

 the north to middle Sweden, and in Finland. 



Remarks: Zetterstedt has a curious note under this species, as 

 he says: "$ vivipara", but without further statements. 



23. T. exilis Meig. 



1822. Meig. Syst. Beschr. III, 90, 54. — 1862. Schin. F. A. I, 91 

 (Platypalpus). — 1903. Kat. palåarkt. Dipt. II, 283. 



Male. Frons and vertex grey or dark grey; epistoma black, 

 shining, very narrow; palpi somewhat large, white, more than half 

 as long as the proboscis; the latter black at the apex. Occiput grey, 

 with yellow bristles above, white hairs below. Antennæ brown, the 

 basal joints yellow, the third joint a little elongated, but shorter than 

 the arista. Thorax yellow, a little pruinose but somewhat shining. 

 The dorsocentral and acrostichal hairs as usual uniserial and biserial 

 respectively ; only one long dorsocentral bristle behind ; two distinct 

 notopleural bristles present; all bristles and hairs yellow. Scutellum 

 with two yellow marginal bristles, and on each side a small hair. 

 Pleura yellow, slightly pruinose; above the middle coxæ a shining 

 spot. Abdomen yellow, the middle segments generally black; it is 

 clothed with short, yellow hairs. Venter yellow. Legs yellow, the 

 last tarsal joint distinctly black; the front tarsi simple. The front 

 femora slightly, the middle femora a little more thickened; the middle 

 tibiæ short, the apical spine small. The legs are yellow haired, there 

 are no long bristles on the postero-ventral side of the middle femora, 

 but the spines in the row here are long and more bristle-like. Wings 

 yellow, with likewise yellow veins; the postical cross-vein a little 

 nearer to the base than the middle cross-vein.^ Halteres pale yellow. 



Female. Similar to the male ; abdomen always quite yellow, and 

 pointed. 



Length 2—2,5 mm. 



1 This character, ah-eady noted hy Meigen, needs some explanation. In all 

 species of Tachydromia the two cross-veins are placed quite near to each other, 

 but the exact piacement may vary a little in the same species, the postical 

 cross-vein, however, is always just below, or behind the middle cross-vein; in 

 the former case the two cross-veins form an angle with the tip towards the 

 base of the wing; exilis is the sole species, in which the postical cross-vein is 

 placed a little more basally than the middle cross-vein ; but also in this species 

 the place is not always the same, and sometimes it may lie just below the 

 middle cross-vein. 



