Dexiosoma. 271 



Length 7,5 — 10,5 mm. 



D. vacua is less common in Denmark than rustica; Ordrup Mose, 

 Lyngby Mose, Ørholm, Ruderhegn, Nøddebo, Humlebæk, at Sorø, 

 and in Jutland at Gram and at Skørping; the dates are ''/^ — ^9^^^ 

 The species is known to be parasitic on Melolontha-ldLrvæ. 



Geographical distribution: — Europe; towards the north to 

 middle Sweden, and in Finland. 



53. Dexiosoma Rond. 



Somewhat large species of bright yellowish to greyish colour. 

 The genus is nearly related to Dexia. Head not broader than thorax, 

 slightly convex behind and a little puffed out below, much higher 

 than long. Frons narrow in male, broad in female, somewhat pro- 

 truding. Jowls half as broad as the lieight of the eye or fully. In 

 both sexes no ocellar and only inner vertical bristles, in female further 

 two orbital bristles. Behind postocular bristles black hairs above. 

 Frontal bristles reaching to insertion of antennæ, all crossing in male, 

 in female an outwards directed bristle above. Cheeks with fine hairs. 

 Vibrissal ridges strongly converging just below, almost meeting in 

 the middle, the epistoma thus here much narrowed; a large vibrissa 

 on the angle, somewhat above lower margin of epistoma, no vibrissæ 

 above it. Epistoma almost not retreating, deeply excavated, without 

 carina, the lower narrow part protruding. The lower margin of the 

 jowls curving upwards anteriorly. Oral aperture not large; oral 

 bristles strong, few in number, sometimes only two. Oral cone and 

 pp^JWTScis short; clypeus small, horse-shoe-shaped; labium slightly 

 chitinised, yellow, labella large. Palpi thread-like. Antennæ inserted 

 a little below middle of the eye, reaching to about the end of the 

 excavated part of epistoma, third joint at least thrice as long as second, 

 second with very small bristles or hairs; arista long-plumose. Thorax 

 rectangular; three postsutural dorsocentrals and only a præscutellar 

 pair of acrostichals. Scutellum with three marginal bristles on each 

 side. Three sternopleural bristles. Pteropleura with a bundle of hairs 

 and a long bristle above. Abdomen long, elongated conical; excava- 

 tion on second segment reaching the hind margin; only marginal 

 bristles, none on second segment; fifth with a double row of bristles. 

 Legs long, with long tarsi which have elongated joints; claws and 

 pulvilli in male strongly elongate. Wings with first posterior cell 



