Xylota. 525 



as in nemorum but the fourth segment is quite black-haired except 

 at tlie basal corners, and the hairs are all short, not long at the hind 

 margin; the pale hairs on the second pair of spots are decumbent, 

 not erect as in nemorum. Genitalia yellow-haired. Venter yellowish, 

 black at the base and on the apical part; it has short, pale hairs, 

 long only at the base and partly on fourth segment and here darker. 

 Legs black, about the basal third of the tibiæ, or on hind tibiæ some- 

 what less, and the two first joints of anterior tarsi yellow and also 

 the third joint somewhat pale; hind trochanters with a short spur or 

 process below near the apex ; hind femora almost not thickened, below 

 they are covered with quite short black spinules or bristles and there 

 are two rows of small spines, the row on the anterior side stretcliing 

 towards the base, the other present only on the apical third; hind 

 tibiæ relatively longer than in nemorum., very slightly curved ; the legs 

 are rather short-haired, the hairs are whitish or yellow, behind the 

 apex of anterior femora are some black hairs; the short hairs on a 

 large apical part of hind femora are black and towards below the 

 black hairs stretch inwards almost to the base; also at the apex of 

 niiddle femora and to a slight degree on front femora are short, black 

 hairs; the hairs on tibiæ are yellow, below hind tibiæ darker to 

 blackish, but there is no erect ciliation. Wings a little brownish 

 tinged, especially towards the anterior margin ; medial cross-vein rather 

 oblique, placed after the middle of the discai cell. Stigma brown. 

 Squamulæ whitish with yellow margin and fringes. Halteres yellow. 



Female. Vertex and frons somewhat narrow, widening down- 

 wards, black or bluish black; frons with large, grey dust spots nearly 

 meeting in the middle; the hairs are short, yellow, the space above 

 the antennæ bare. Abdomen with the spots smaller and more 

 triangular than in the male, and generally quite or nearly quite 

 glaucous ; the fourth segment has similar, glaucous, more or less distinct 

 spots ; abdomen is all black-haired with only the spots distinctly white- 

 haired. Hind femora as in the male but without spinules below the 

 basal part. 



Length 10—11 mm. 



This species is somewhat similar to nemorum but it is conspicuously 

 larger, and it is easily known by the much thinner hind femora, the 

 shorter and less curved hind tibiæ \vith no erect ciliation below, and 

 in the male by the short spur on the hind trochanters and besides 

 there are more characters as the colour and length of the pubescence 

 on fourth abdominal segment and still other characters. It is very 

 similar to X ahiens Wiedem., which will perhaps be found in Den- 

 mark, but that species is smaller, with shorter hind legs and thicker 



