220 P. CAMERON. HYMENOPTERA. 



the apex of the metathorax, extending to the lower edge of the pleurae, the centre with a 

 triangular incision at the base and apex, the apical incision larger than the basai, a longish 

 oval spot immediately under the hind wings, a large, oblique square mark on the metapleurae, 

 nearer the apex than the base, the sides of the i st abdominal segment narrowly on the basai 

 half, the apical more widely, and extending on to the top, the apex of the black part 

 projecting into the yellow, which is continuous at its apex; the apex with a triangular black 

 mark, a mark in the centre of the 2nd segment on the sides, the basai half widened above, 

 the narrowed lower part running along the lower edge of the segment and as long as the 

 dilated basai part, a spot, slightly wider than long, on the basai half of the y A segment on 

 the sides, the 4A from the base to near the apex, the centre with an irregular triangular 

 incision, the apical edge irregular, more than apical half of the 5H1, the sides of the mark, 

 slightly obliquely narrowed, the apical half of the genitial armature and the i st ventral segment, 

 whitish yellow. Fore legs whitish yellow, the femora and tibiae tinged with fuscous above, the 

 middle coxae white, the apical third black, the basai joint of the trochanters white, the apical 

 black, as are also the femora, the base of the tibiae narrowly, the apical two-thirds, the base 

 of the metatarsus to shortly beyond the middle and the terminal joint, as well as the spurs; 

 the middle tarsi black, with the 3 rd joint white. Wings hyaline, the nervures and stigma 

 black, the areolet represented by a short thickened transverse cubital nervure, the récurrent 

 nervure received very shortly beyond it. cf. 

 Length 13 m. m. 



Mesostenoideus, Ashm. 



The following table may aid in the détermination of the species of Mesostenoideus 

 I hâve described. 



1 (4) Mesonotum with a conical yellow mark. 



2 (3) Metanotal spines separated, the 2 spots on mesopleurae of nearly equal size, the basai 



half of hind femora white on the inner and outer side .... spilonotus. 



3 (2) Metanotal spines united, the mark covering them narrowed behind, the lower spot on 



mesopleurae much smaller than upper, hind femora broadly rufo-fulvous above . Frederici. 



4 (1) Mesonotum immaculate. 



5 (6) Metanotum with no mark; the 2 spots on vertex united below, leaving a black triangular 



spot in the centre of the vertex trianguliferus. 



6 (5) Metanotum maculate apart from the spines, the yellow marks on the vertex separated below. 



7 (14) Metanotum unimaculate. 



8(11) The mark large, not narrowed at the base, the spines black. 



9(10) The mark almost touching the basai keel, the mark on metapleurae touching the pleural 

 keel, extending below the middle, the apex equally narrowed to a point in the middle 



megaspilus. 



10 (9) The mark clear from basai and pleural keels, the pleural mark clear from pleural keel, 



broadly, roundly narrowed behind nigrispinus. 



11 (8) The mark small, narrowed at the base, the spines white. 



12 (13) Abdominal pétiole black, metanotal mark transverse behind, the spot behind posterior 



wings not narrowed and prolonged inwardly ....... tanyopus. 



13(12) Abdominal pétiole at base and sides white, the mark behind the wings narrowed and 



prolonged inwardly ........... varipetiolatus. 



14 (7) Metanotum bimaculate. 



15(18) The marks separated; the face immaculate. 



