Xylola. 513 



sometimes slightly and indefinitely paler at the hind margin; abdomen 

 is more or less duU along tlie middle of second and third segments 

 and at the hind margin of the latter; it is clothed with short hairs, 

 which are yellow but on fourth segment black except on and at the 

 sides, they are also often blaclc on the hind margin of third segment 

 and sometimes in the middle at the hind margin of second; towards 

 the sides they are longer and longest towards the base and at the 

 basal corners. Genitalia with yellow or partly black hairs. Venter 

 coloured mainly as dorsum, with short, pale hairs, longer at base and 

 apex, and darker to blackish at the end of fourth segment. Legs 

 black, the very apex of anterior feraora yellow; anterior tibiæ yellow 

 with a larger or smaller, black ring near the apex, sometimes they 

 are almost quite yellow, anterior tarsi with the three lirst joints yel- 

 low; hind tibiæ with the basal third yellow, hind tarsi blackish or 

 with the three basal joints more or less yellow, only metatarsus dark 

 above; hind femora somewhat thickened, hind tibiæ somewhat com- 

 pressed and somewhat strongly curved in the apical third; hind troch- 

 anters with a strong, spine-like process below, directed backwards; 

 hind femora with two rows of short, strong spines below, the row 

 towards the posterior side present only on the apical part; the legs 

 short-haired, also the femora with only longish hairs; the hairs whitish 

 to more or less dark yellow, just at the apex of front femora may 

 be a few black hairs and the short hairs on the apical part of hind 

 femora are black. Wings more or less brownish tinged, sometimes 



Fig. 173. Wing of X.segnis d". 



almost hyaline. Stigma brown. Squamulæ pale yellow with darker 

 margin and fringes. Halteres pale yellow. 



Female. Vertex and frons rather narrow, slightly widening down- 

 wards, bluish and shining; frons with a pair of whitish dust spots 

 nearly meeting in the middle; the hairs short, pale, the space above 

 the antennæ bare. Hind trochanters without spine, hind femora less 

 thickened than in the male, the spines less strong and those in the 

 anterior row produced less towards the base. 



33 



