Empididae. 57 



as a black, somewhat thick t.hread, curved forwards, often vvith the 

 apex stretching in under the foregoing dorsal segment. Legs black 

 or slightly brownish black, shining; coxæ greyish pruinose; front 

 feniora with antero- and postero-ventral rows of short, fine hairs; 

 posterior femora with similar rows of somewhat longer hairs; front 

 tibiæ short-haired below, slightly longer-haired and with some bristles 

 above; middle tibiæ haired in the same way, but the hairs a little 

 longer and also a few short bristles ventrally ; hind tibiæ with moder- 

 ately long hairs on the ventral side, and with long hairs and two 

 rows of thin bristles on the dorsal side. Anterior tarsi short-haired 

 and the metatarsi somewhat spinulous below, the spines longest on 

 the middle tarsi; hind metatarsi with long hairs above and stronger 

 spinulous below. All hairs and bristles black or brownish black; 

 there is no dense pubescence discernible below the posterior femora. 

 Wings hyaline, slightly yellowish tinged. Veins paler on darker brownish, 

 anal vein distinct, reaching the margin. Stigma yellowish, only little 

 conspicuous. Balteres white or yellowish white. 



Female. Frons broad, grey. The hairs on thorax of the same 

 length as in the male, those on abdomen only slightly shorter; the 

 three stripes on thorax more conspicuous; the styles of the ovipositor 

 somewhat long. Legs simply and shorter-haired, the bristles on the 

 hind tibiæ shorter and no long hairs on the hind metatarsi. Wings 

 slightly more tinged. 



Length 3,8 — 4,5 mm. 



This species is distinguished by its somewhat robust shape, the 

 structure of the male genitalia and the immaculated or slightly striped 

 thorax. 



Rh. simplex is not common in Denmark, but may sometimes be 

 present in somewhat great number on suitable localities ; Charlotten- 

 lund at the shore, Vester Fælled, Amager Fælled; in Jutland on 

 Tipperne in Ringkjøbing Fjord and at Nymindegab. It occurs in 

 grass and low herbage on meadows and commons, and always near 

 the shore. It is a spring species, my dates are only ^/e — ^"/o. I have 

 examined Stæger's specimens which Zetterstedt mentions as sent to 

 him under the name of laevipes var. 



Geographical distribution:— The species is hitherto only known 

 from the southernmost Scandinavia, Denmark and England. 



12. Rh. tibiella Zett. 



1842. Zett. Dipt. Scand. 1, 432, nota, et 1849. VIII, 3044, 54—55. — 

 1903. Kat. palåarkt. Dipt. II, 230. 



