80 THE GROUP OF CRASSUS. 



joints equal. Front smooth, its sutures obsolete ; clypeus 

 transverse ; pleurce and breast smooth, shining ; thorax 

 covered with dense silky pubescence. 



From the preceding section the present is known by 

 the smooth front and breast, by the short, thick an- 

 tennae, and by the thorax being covered by soft silky 

 pubescence. The antennae are shorter in both sexes 

 than in any other British species of Nematus. 



23. NEMATUS PARVICORNIS. 



Nematus Iremcornis, Thorns., Opus., 622, 18 ; Hym., Scand., i, 



100, 25; Andre, Species, i, 

 169, Cat., 19,* 103 (non Foer.). 

 parvicornis, Kirby, List of Hymen., i, 118, 116. 



Black, smooth, shining ; head (especially) and thorax covered with 

 close silky pubescence ; apex of clypeus, labrum, tegulee, pronotum, base 

 of costa, legs, and apical half of abdomen beneath, with the anal parts 

 whitish-testaceous. Base of coxee, a splash on the underside of posterior 

 femora, with apex of posterior tibias and tarsi, black. Antennae shorter 

 than body, thick, compressed at base, tapering towards the apex, the 

 third joint of the same size as fourth, curved beneath, and not longer 

 than the longitudinal diameter of eye. Wings hyaline, the greater part 

 of costa and stigma fuscous ; third cubital cellule double so long as 

 broad ; basal nerve almost joined to costal. The eyes are large, oval, the 

 clypeus small, truncated at apex ; palpi long, white ; mandibles piceous. 



The $ according to Thomson is similarly coloured to the $ as 

 described above, the apex of abdomen and belly being dirty-testaceous. 



Length 2^ lines. 



I bred this species from larvae found on birch in 

 Sutherland shire in June. The larva had a black head, 

 and a yellowish-green body marked with orange spots 

 and minute black points. The flies appeared in July. 



Sutherlandshire. 



Continental distribution : Sweden. 



VI. THE GROUP OE CRASSUS. 



Body entirely black, legs red save the base, hind tarsi 

 and apical half of tibia?, which are thickened and 



