Empididae. 271 



rows of short spines below, the middle femora a few longer hairs 

 below at the base, and the hind femora are distinctly haired below. 

 Wings blackish brown with about the basal third part hyaline, some- 

 what white, and with a hyaline spot in the second posterior cell, 

 stretching also a little above the discai vein, or also the first posterior 

 cell almost quite hyaline. Veins brown. Halteres white. 



Female. Similar to the male, but the anterior femora less thickened, 

 and the middle tibiæ not curved at the apex. 



Length about 2,5 mm. 



This species is at once recognised by the colour of the wings, 

 and in the male by the strongly swoUen front femora. As Zetterstedt 

 says: „Stæg. in litt." the name f enestrata was due to Stæger. 



T. sahulosa is rare in Denmark and has hitherto only been taken 

 in Jutland at Silkeborg (as mentioned by Zetterstedt) and at Frederiks- 

 havn (Th. Mortensen), six specimens in all ; it has been taken in July. 

 It occurs running in the sand at the horders of streams and at the 

 sea-shore. 



Geographical distribution:— Northern and middle Europe down 

 into Germany; its northern limit lies in Denmark. 



4. T.terricola Zett. 



1819. Zett. Vetensk. Akad. Handl. 1819, 81, 34 {Tachydromia). — 

 1822. Meig. Syst. Beschr. III, 72, 9 {Tachydromia). — 1823. Fall. Dipt. 

 Suec. Suppl. I, 6, 20—21 {Tachydromia). — 1842. Zett. Dipt. Scand. I, 

 320, 9, et 1849. VIII, 3011, 9 {Tachypeza). — 1860. Loew, Zeitschr. fur 

 Entom. Breslau, XIV, 17, 1. — 1903. Kat. palaarkt. Dipt. II, 277. 



Male. Frons and vertex black, shining, the former narrow; palpi 

 somewhat short, yellow haired, with a black bristle at the apex. 

 Occiput black, shining, with a few black bristles above. Antennæ 

 yellow, the arista slightly darker. Thorax black, shining, with very 

 short, black hairs. A notopleural and a postalar bristle present, both 

 black. Scutellum with two black marginal bristles. Pleura black, 

 shining; the propleural parts whitish pruinose, so that there is a 

 large, whitish spot above the front coxæ. Abdomen black, shining, 

 with short, brownish hairs. Venter black. Exterior genitalia and the 

 last ventral segment with somewhat long, dark hairs. Legs yellow; 

 sometimes the tibiæ and the hind femora at the apex a little brownish; 

 the front tarsi with the apex of the metatarsus and the whole fourth 

 and fifth joint brown; on the posterior tarsi the apex of the three 

 first joints and the two last joints quite or almost quite brown. The 

 anterior femora only slightly thickened; the middle femora at ;the 

 base with a little excision, beset with blackish bristles. For the rest 



