1 



North American Hymenojptera. 281 



4. B, centratus. Black ; tarsi and tip of the tiblse 

 obscure piceous. 



Inhabits Indiana. 



Bodij black, polished, with scattered hairs: antennce 

 with an obsolete piceous tint, excepting the basal joint: 

 metathorax \y\ih discoidal punctures and lineations; wings 

 hyaline; two brachial cellules; a simple, short, oblique 

 reciilinear Inflection of the tip of the radial nervure 

 pointing towards the centre of the wing ; nervures pale : 

 tergum polished: tibice and tarsi obscure piceous; the 

 latter blackish at tip. 



Length less than three tw^entieths of an inch. 



This species is considerably larger than the preceding 



dilFers 



COPTERA, Nob. 



ARTIFICIAL CHARACTER. 



Wings without nervures; superior wings folded and 

 with a fissure at tip; abdomen of two segments. 



NATURAL CHARACTER. 



Body moderately slender: head longitudinally oblong, 

 truncate or a little excavated before, over the insertion of 

 the antennae : eyes lateral, rounded, entire : stemmata 

 three : antenna submoniliform, graduUy enlarging a little 

 towards the tip; basal joint longest and dilated: wings 

 without obvious nervures; superior wings large, folded 

 longitudinally in two, and at the tip of the fold with a 

 profound fissure ; inferior wings rather slender: aldomen 

 composed of but two segments, of which the basal one is . 

 somewhat petioliforra : feet moderate. 



VOL. I. FART III. 37 



