Empididae. 55 



the leaves; the females were only present in small number, likewise 

 sitting on the underside of the leaves, and here the males were also 

 found during the day. 



Geographical distribution : — Northern and middle Europe, from 

 Germany to northern Scandinavia but there rare, 



10. Rh. obscura Zett. 



1838. Zett. Ins. Lapp. 564,10. — 1842. Zett. Dipt. Scand. I, 429, 50. 

 — 1903. Kat. palaarkt. Dipt. II, 228. 



Male. Eves contiguous; epistoma dark. Oceiput dark grey, with 

 black hairs. Labrum about as long as the head is high. Antennæ 

 almost of the length of the head, or slightly longer, black, the two 

 basal joints very short-haired, the third elongate. Thorax brownish 

 black, duU, with very faint traces of three darker stripes. The dorso- 

 central and acrostichal bristles of moderate length, black; the former 

 uniserial and longer behind, the latter biserial. Further a humeral bristle, 

 a posthumeral, a pair of notopleural and supraalar and a postalar 

 bristle, all black; besides there are a few weaker hairs. Scutellum 

 has four black marginal bristles. Pleura dark greyish, metapleura 

 with black hairs. Abdomen robust, greyish black, duU; it is densely 

 clothed with somewhat short, black hairs, longer at the sides, especi- 

 ally in front. Venter blackish grey with somewhat short hairs. Exterior 

 genitalia somewhat resembling those in tarsata, the lower lamellæ 

 directed more or less upwards, not very broad, with long hairs at 

 the lower (posterior) margin ; the upper lamellæ lylng in front of the 

 lower, styliform. The eighth ventral segment arched, with long black 

 hairs at the hind margin. Penis thread-like, black, curved upwards, 

 a little sinuous and with a curious loop near the base. Legs black, 

 slightly shining; coxæ greyish pruinose; anterior femora with short 

 hairs above and rows of slightly longer, fine hairs below, hind femora 

 with somewhat longer hairs above ; posterior femora with the short, 

 dense pubescence below, but scarcely observable. Anterior tibiæ 

 short haired with a few bristles on the dorsal side ; hind tibiæ short- 

 haired on the ventral side, but somewhat densely and long-haired on 

 the dorsal side, and between the hairs some bristles. Anterior tarsi 

 short-haired, the middle ones slightly spinulous beneath, hind tarsi 

 somewhat long-haired above and with a few bristles, slightly spinulous 

 below and also here with the hairs of some length. All hairs and 

 bristles black. Wings a little greyish tinged; veins brownish to 

 blackish brown, anal vein distinct and reaching the margin. Stigma 

 very faint, brownish. Balteres yellowish white. 



