MONOGRAPH OF THE NORTH AMERICAN PROCTOTRYPID^. 221 



OPISTHACANTHA Aslini., gen. iiov. 

 Baia Aahm., MS. (Oliui.). 



(Type, O. vuUijxn Ashin.) 



Head transverse, the occiput aud cheeks delicately margined; ocelli 

 3, triangularly arranged, the lateral close to the eye; eyes large, oval, 

 pubescent. 



Antenna? inserted at the clypeus, 12 iointe<l in both sexes, in the 9 

 short, clavate, the club 6-jointed, the last funiclar joint very minute; iu 

 S filiform, submoniliform. 



Mandibles bidentate. 



Thorax short, ovoid, the prothorax not visible from above; mesono 

 turn with 2 delicate but distinct furrows; scutellum semicircular; ])ost- 

 scutellum produced into a short, acute spine; metathorax very short, 

 angles subacute. 



Front Avings ciliated, the sul)marginal vein reaching the costa a little 

 before half the length of the wing; marginal vein short, not half the 

 length of the stignial; postmarginal greatly lengthened; the stigmal 

 vein oblique, knobbed; basal vein and basal cell present. 



Abdomen oblong-oval, the second and third segments the longest, 

 the third a little longer than the second. 



Legs slender, the tibial spurs 1, 1, 1, weak, the basal joint of hind 

 tarsi about 4 times as long as the se(;ond. 



In general appearance this genus closely resembles a Telenomid, but 

 the venation, carinated abdomen, and the spined postscutellum readily 

 distinguish it. 



Opisthacantha niellipes, sp. uov. 



(Pl.ix,Fig.4, 9-) 



S 9 . Length, 1.40""". Black, subopaipie, the punctuation so fine 

 as to be scarcely iierceptible. Head transverse, broader than the 

 thorax. Eyes very large, pubescent, the space between them narrow. 

 Lateral ocelli close to the eye. Mandibles 3-dentate, brown. Autennai 

 12-jointed, browu-black, the scape yellow; in 9 clavate, pedicel small, 

 the first funiclar joint slightly longer than the pedicel, about twice- as 

 long as thick; the second and third moniliform, the fourth very minute; 

 the club large, the joints scarcely separable, transverse; in S fili- 

 form, the pedicel moniliform, the first and third funiclar joints about 

 equal, long-oval, the secoiul small, the joints from the fourth to the 

 twelfth oval- moniliform, the last ovate, longer than the preceding. 

 Mesouotum with two nearly parallel furrows. Scutellum subconvex, 

 with a transverse line at base. Postscutellum armed with an acute 

 spine or thorn. Legs pale honey-yellow. Wings hyaline, the venation 

 pale brown; the basal nervure delicate, but distinct; the marginal, 

 about as long as the stigmal; the stigmal rather short, oblique, and 

 ending in a knob; postmarginal \ein very long. Abdomen long-oval, 

 longer than the head and thorax together; black, with a brownish tinge 



