Xylota. 523 



the margin ; abdomen is clothed with short iiairs, which on second and 

 tiiird segments mainly follow the ground colour, they are depressed 

 on the black parts but erect on the spots; the fourth segment has 

 mainly yellow hairs but some black in the middle on the front part; 

 they are long and reddish yellow at the hind margin; towards the 

 sides of abdomen the hairs are longer and at the side margin all 

 yellow, and long at the basal corners. Genitalia yellow-haired. Venter 

 yellowish, blaekish on first and fourth segments; it is clothed with 

 longish, pale hairs, shorter on fourth segment but long and dense at 

 its hind margin. Legs black, the anterior knees, the extreme base of 

 hind tibiæ and the two basal joints of the anterior tarsi yellow or 

 reddish yellow; the third joint of the anterior tarsi often brown, and 

 likewise second joint of hind tarsi; hind trochanters simple, hind 

 femora considerably thickened, thickest about or a little beyond the 

 middle; below they have numerous, very short, black spinules, only 

 at the apex some longer spines in two rows; hind tibiæ rather short, 

 somewhat compressed and distinctly curved; the legs are somewhat 

 short-haired, the hairs mainly yellow, behind the apex of anterior 

 femora some black hairs and the short hairs on the apical part of 

 hind femora are black; also below middle tibiæ are black hairs, and 

 the hind tibiæ have a short, erect, very dense, black ciliation below. 

 Wings a little brownish tinged; medial cross-vein not very oblique, 



Fig. 174. Wing of X. nemorum ^. 



near the middle of the discai cell. Stigma yellowish brown. Squamulæ 

 whitish with yellow margin and fringes. Halteres yellow. 



Female. Vertex and "frons somewhat broad, widening downwards; 

 they are æneous black, somewhat shining; frons with two grev dust 

 spots, almost or quite united in the middle ; the hairs are black above, 

 yellow below, a small space above the antennæ bare. Abdomen 

 relatively broad, with the spots generally smaller and more or less 

 obscurely yellowish or quite glaucous ; it is black-haired with the spots 

 and all the fourth segment conspicuously pale-haired, on the latter the 

 hairs long at the hind margin as in the male. Hind femora a little 



