Empididae. 59 



the male, hind tibiæ compressed, pennate on the dorsal side, the 

 hairs simple and short at the base, but outwards soon becoming long 

 and scaly. Wings slightly yellowish tinged. 



Length about 2^5 mm. 



This species is recognisable by the colour, the shape of the male 

 genitalia and the way in which the legs in the female are pennate. 

 I have examined Stæger's specimens, mentioned by Zetterstedt 1. c. 

 The species may vary somewhat in the colour of abdomen, genitalia 

 and legs, these parts being darker or lighter, the latter perhaps to 

 some degree due to the degree of maturity; whether abdomen is 

 darker or lighter it is hovvever always grey or greyish. — As Zetter- 

 stedt says: „Stæg. in litt." the name is originally due to Stæger. 



Bh. tihiella is not at all common in Denmark, I only know five 

 specimens; Charlottenlund (Stæger), Bøllemosen (the author). It occurs 

 in fens and on other humid localities in woods; it is a spring species, 

 my dates are ^^/o — ''/u. 



Geographical distribution: — The species is only known from the 

 southern Sweden to Germany, and it occurs also in England (according 

 to specimens sent to me from Mr. Verrall.). 



13. Rh. plumipes Fall. 



1815. Fall. Dipt. Suec. Enipid. 25, 23 (Empisl. — 1822. Meig. Syst. 

 Beschr. III, 47,11. - 1842. Zett. Dipt. Scand. I, 426,47. — 1862. Schin. 

 F. A. I. 100. — 1903. Kat. palåarkt. Dipt. II, 229. — Rh. geniculata: 1842. 

 Zett. Dipt. Scand. I, 427, 48 et 1849. VIII, 3042, 48. 



Male. Eyes contiguous, the small frontal triangle grey; epistoma 

 grey. Occiput likewise grey, with black, just below a little brownish 

 hairs. Labrum as long as the head is high or slightly longer; palpi 

 dark, with dark hairs. Antennæ of the length of the head, black or 

 brownish black, the two basal joints sometimes paler to reddish, 

 with short hairs; the third joint somewhat elongated, and attenuated 

 towards the apex. Thorax duU grey with three indistinct stripes, the 

 lateral slightly brownish, the median grey and very indistinct. The 

 dorsocentral and acrostichal bristles of moderate length, black, biserial, 

 the hinder dorsocentral bristles long. Further a humeral bristle, a post- 

 humeral, three notopleural, a pair of supraalar and a postalar bristle, 

 all black. Otherwise there are almost no other bristles or hairs on 

 the sides of the disc. Scutellum grey, with four black marginal 

 bristles, the exterior very small and often wanting. Pleura grey, 

 metapleura with black hairs. Abdomen dull grey, sometimes a 

 slightly yellowish or brownish colour shines through the grey pruinosity, 

 but even then the abdomen is mainly greyish; the hind margins of the 



