340 HYMENOPTERA ACULEATA. 



narrow and fragile, eighth broad and subquadrate, with a 

 slight apical projection, armature with the stipites suddenly 

 thickened at the apex, forming a sort of four-sided 

 truncate club ; ? without any observable pollen brush. 

 The British species of this genus are parasitic on Osmiu, 

 but some of the foreign species associate with Anthidinm 

 and other genera. The genus is of very limited extent. 

 Smith says it occurs in Siberia, India, North China, and 

 United States. We have three species in this country 

 which are easily distinguished. 



(4) 1. Abdomen unspotted. 



(3) 2. Posterior margins of the segments pale . aiekeima. 



(2) 3. Posterior margins of the segments not 



pale PHffiOPTERA. 



(1) 4. Abdomen spotted at the sides . . octomaculata. 



S. aterrima, Pans, {inmclulatisdma, Kirh.). — Black, 

 head and thorax dull, closely and deeply punctured, clothed 

 sparingly with greyish hairs, tegulse black, wings dusky, 

 marginal cell brown anteriorly, scutellum with an angular 

 tooth on each side of its base ; abdomen slightly shining, 

 sparsely clothed with very short greyish hairs, very 

 largely and deeply punctured, posterior margins of the first 

 four segments pale testaceous, sixth segment in the J* 

 rounded at the apex, seventh only visible ventrally, four 

 ventral segments visible, the second, third and fourth 

 ■with their apical margin fringed with long golden hairs, 

 the two latter concave and densely pubescent, fifth and 

 sixth excavated and clothed with golden hairs, eighth 

 produced at the apex into two little round processes, 

 armature with the stipites each terminating in a four-sided 

 club, sagittas short and slightly pointed, ? with the six 

 ventral segments exposed, shining, largely punctured and 

 sparsely clothed with golden brown hairs. 



L. 8-9 mm. 



The least rare species of the genus but far from common. 



