Empididae. 61 



nate on the dorsal and ventral side; middle tibiæ ciliated on both 

 sides, tlie hairs on the dorsal side slightly scaly; the hind femora 

 and tibiæ compressed, pennate on the dorsal and ventral side, the 

 scaly hairs longest on the ventral side of the femora, short towards 

 the apex on the dorsal side, and on the ventral third part of the 

 tibiæ. Wings somewhat brownish tinged. 



Length 3,5 — 5 mm. 



This species may easily be recognised by the male genitalia, and 

 the way in which the legs of the female are pennate; as seen from 

 the description it may vary somewhat in colour, especially of the 

 legs, these being darker or lighter, but again I think that this varia- 

 tion is to some degree dependent on the maturity, but also in the 

 fully mature specimens some variation exists. 



Bh. plumipes is not rare in Denmark, though it has not been 

 taken many times, and I only know it from Lersøen and Amager 

 Fælled; it seems to prefer somewhat humid piaces. Zetterstedt 

 records, that it hovers in the air towards evening. My dates are 

 only '^/o— ^''/e, but it is not exclusively a spring species as Zetterstedt 

 records it from ^°h, — ^/s. 



Geographical distribution: — Northern and middle Europe down 

 into France; towards the north to northern Scandinavia, and in 

 Finland. 



Remarks: I feel sure, that Rh, geniculata Zett. (= plumipes^ Fall. 

 var. pedibus obscuris) is identical with plumipes, as also suggested 

 by Schiner and Scholtz (Zeitschr. fiir Entom. Breslau, V, 1851, 55) 

 (though these authors partly refer to geniculata Meig.); I have 

 examined Stæger's specimens of geniculata which Zetterstedt had 

 seen, and they are in all respects agreeing with plumipes and especially 

 in the structure of the male genitalia, the hairiness of the legs in the 

 male and the way in which the legs in the female are pennate, and 

 they show every intermediate stage in the colour of the legs, from 

 black to somewhat light brownish, but always with the knees more 

 or less, sometimes very slightly, pale. In Kat. palåarkt. Dipt. geniculata 

 Zett. is placed as synonym to gracilipes Loew, I think on Loew's 

 authority; I do not know this species, but according to the descrip- 

 tion (Programm 1840,22, IG) I think the Identification is not correct; 

 Loew, who had only the male, makes no mention of the curious 

 genitalia, and his expression, that the front legs are specially long, 

 so that the species is similar to a Hemerodromia, seems not to agree 

 with geniculata Zett. Rh. geniculata Meig. seems to be another species. 

 — Whether plumipes Meig. is really the present species is doubtful, 

 as Meigen says, that the front femora are pennate below. 



