HYMENOPTERA FROM SARAWAK. 55 



lighter in colour than the other segments ; its central region is 

 broadly black except narrowly down the middle ; the second 

 segment is black at the base to near the middle ; the third has 

 the basal third black ; the fourth and fifth are more narrowly 

 black at the base. On the metapleuree. are, in the middle, four 

 short stout keels ; the middle two are longer than the others. 



Ac leas a, gen. no v. 



Median segment reticulated all over, without transverse 

 keels ; the apex with two large conical teeth. Thorax about 

 three times longer than broad ; the mesonotum with indistinct 

 parapsidal furrows, and coarsely reticulated. Metapleural keels 

 absent. Areolet large, wider than long, of equal width 

 throughout ; the transverse cubital nervures slightly oblique ; 

 the apical one distinct ; the transverse median nervure is receiv- 

 ed behind the transverse basal ; the transverse median nervure 

 in hind wing broken shortly below the middle. Legs of 

 moderate length ; the basal joint of the hinder tarsi is thick- 

 ened ; the claws are small. The petiole becomes gradually 

 wider towards the apex ; its sides near the middle on the lower 

 side project into a stout triangular tooth, the part behind this 

 beiug keeled ; in front of it is a rounded tubercle. The head is 

 rather narrow ; the eyes are large and projecting ; the front is 

 stoutly striated in the middle ; the front and vertex are depressed ; 

 the eyes project above the vertex ; the sides of the pronotum 

 are indistinctly toothed at the base ; they project at the teguhe ; 

 the scutellar depression is larger and deeper than usual and 

 bears four longitudinal keels. 



A distinct genus of Mesostenini easily known by the com- 

 pletely reticulated median segment -without transverse keels, by 

 the stoutly spined petiole, by the raised scutellum, by the 

 coarsely reticulated thorax, and by the thickened base of the 

 hinder tarsi. 



Acleasa albispi?ia, sp. nov. 



Nigra, scutello spinisque albis ; abdomine rufo-balteata ; 

 pedibus flavis, coxis, trochanteribus posticis apice femorum 

 posticorum apiceque tibiarum posticarum nigris ; alis hyalinis, 

 nervis stigmatique nigro-fuscis 9 . 



