Empididae. 35 



(Entom. Month. Mag. XLV, 1909, 161) has taken R.sulcata in copula 

 and with prey, and I have taken R. nigripes m the same way. 



The genus comprises about 155 species from the palæarctic 

 region; 22 have hitherto been found in Denmark. It is essentially a 

 boreal genus, thus two species occur in Greenland, where otherwise 

 of Empids only Clinocera stagnalis occurs, and four species occur on 

 Nova Zembla. Zetterstedt has 79 species from Scandinavia, and even 

 if this number is too great, the number of real species is certainly 

 not small, On the other hånd it is recently shown, that the genus 

 is also well represented in South America in the mountainous regions; 

 Bezzi records (Nova Acta. Abhandl. d. Kais. Leop. Garol. Deutsch. 

 Akad. der Naturf. XGI, No. 3, 1909, 320) that 31 species are known 

 from there. 



Remarks: In the following descriptions I have not given the length 

 of the proboscis, as this character is of no value, since the labium is, 

 as said above, able to be extended to a great length when its basal 

 connecting membrane is fuUy dravvn out; I have on the contrary 

 given the length of labrum, though also this length may be somewhat 

 varying, according as the oral cone is folded in or more dravvn 

 out. I shall also note, that nearly all species with dark legs may 

 have these somewhat varying between black and brown, which is, I 

 think, for a great part due to the degree of maturlty; but also old 

 museum specimens are very often extraordinarily light, probably due 

 to bleaching. 



In the consecutive order in which I have placed the species, and 

 in the analytical table I have to some degree used the groups pro- 

 posed by Frey (Acta Soc. pro Faun. et Flor. Fenn. XXXI, No. 9, 

 1909, 17), but otherwise I think, that such definite groups cannot be 

 established, as the arrangement of the thoracic bristles is much 

 varied and would lead to many more groups. Thus in the group 

 with the eyes in the males separated nigripes has pluriserial dorso- 

 central bristles, dissimilis and spissirostris biserial; the two latter 

 species have hairs behind the humeri, but they are delicate, so that 

 the dorsocentral bristles are distinct from them. In the next group 

 spmipes and sulcata have pluriserial dorsocentral bristles fused with 

 the hairs behind the humeri, but in vesiculosa the dorsocentrals are 

 somewhat distinct from these hairs, and tarsata has biserial dorso- 

 centrals, rather distinct from the hairs at the sides, only somewhat 

 fused with them quite in front; conformis has biserial dorsocentrals 

 with both rows equally long, and uniserial acrostichals, it cannot be 

 placed in Frey's group 4; simplex has biserial, equally long dorso- 

 centrals and biserial acrostichals, it cannot well be placed in Frey's 



