516 Syrphidae. 



at the base, the sides and on fourth segment; it is clothed with short 

 hairs which mainly foUow the ground colour, but there are inconspicuous 

 black hairs forming triangular middle spaces on the red segments, 

 rather extended on third segment; at the side margins the hairs are 

 longer, white, increasing in length towards the base. Venter coloured 

 as dorsum, with short, pale hairs, black on fourth segment; at the 

 base they are longer. Legs with femora black or blackish, the apex 

 of anterior femora yellow; tibiæ and tarsi yellow, the two last tarsal 

 joints more or less darkened; hind tibiæ sornetimes slightly darkened 

 in the middle ; the hind trochanters have a short, conical, pointed pro- 

 cess below, it is directed downwards and is yellow; hind femora 

 considerably thickened, more than in segnis, but they are armed about 

 as in tarda, as they have numerous small spinules below not arranged 

 in rows on the larger part, only at the apex forming two rows of a 

 little larger spinules; hind tibiæ a little less curved than in segnis; the 

 legs haired as in segnis, the hairs whitish,only at the apex of front 

 femora a few black hairs, and the short hairs on the apical part of 

 hind femora and partly below are black; the hairs on tibiæ are fine 

 and dense and cause the tibiæ to shine white or silvery in certain 

 lights. Wings yellowish or light brownish tinged, especially on the 

 middle part. Stigma pale brown. Squamulæ whitish with yellow 

 margin and fringes. Halteres pale yellow. 



Female. Similar to the male; vertex and frons broad, broader 

 than in segnis, widening downwards; they are bluish black, somewhat 

 above the antennæ a greyish pruinose cross-band and the frons 

 pruinose at the sides of the antennæ; the hairs whitish, the space 

 above the antennæ bare. Hind trochanters simple, hind femora less 

 thickened and the spinules below smaller, stretching less near to 

 the base. 



Length 12,5—13 mm. 



This species is easily distinguished by the colour of its legs and 

 the process of the hind trochanters of the male, besides by other 

 characters. 



X. ignava is very rare in Denmark, we have only two specimens, 

 a male and a female; I am not quite certain with regard to ils 

 belonging to our fauna, one of our specimens in the Danish coUection 

 is labelled "Denmark?" and the other has no locality; on the other 

 hånd it is very probable that the species should occur in Denmark as 

 it is found both north and south of us. 



Geographical distribution:— Europe down intoltaly; towards the 

 north to southern Sweden, and in Finland, but not in England. 



