53 



NEW NORTH AMERICAN ACULEATE 

 HYMENOPTERA. 



I5v \Vm I. lo\. I'liil;uk-l|)hia, Pa. 



Myrmosa parvula 



q'. — Clypeus strongly convex medially, more or less depressed on the sides, 

 its anterior margin emarginate in the middle ; front and vertex with tolerably fine 

 punctures, the former with an impressed line down the middle ; antenna; short, 

 stout, the tlagellum of nearly the same thickness throughout the third joint of 

 antenna shorter than the fourth ; thorax coarsely and closely punctured ; meta- 

 tliorax coarsely and closely granulated, with a strong furrow in the middle, exten- 

 ding from base to apex, interrupted at about its middle and strongest on upper 

 surface ; posterior coxrc, as in the other two species armed with a large toolh or 

 spur at base, above ; hind tibire and tarsi very feebly spinose ; abdomen fusiform, 

 finely punctured, the first segment much narrower than the second, giadually 

 widened to the apex, the first and second segments, both above and beneath, sepa- 

 rated by a wide fissure. Black ; tips of mandibles reddish ; head and thorax 

 sparsley clothed with fuscous pubescence ; the mandibles, clypeus. metalliorax 

 and abdomen with pale pubescence ; wings hyaline strongly iridescent, nervures 

 testaceous ; second subniarginal cell fully twice as large as the third, receiving the 

 first recurrent nervure before its middle, the third submarginal receiving the second 

 recurrent at about the middle. Length, 4 mm. 



Southern Illinois [Ro/'crfson). 'I'hc f()ll()\vin<.,r lai)k' will aid in 



(iistincjuishing the three North American species of Myniiosa, the 



males of which are only known. 



Clypeus planate ; head coarsely punctured ; antenmv l<>n_sT, reach- 

 ing about to the apex of scutellum ; second submarjj^inal cell 

 triangular, the first and second transverse-cul)ital nervure 

 meeting at the top; abdomen rather coarsely punctured, first 

 segment of abdomen tlentate beneath unicolor Say. 



Clypeus strongly convex ; first abdominal segment not dentate 

 beneath ; transverse-cubital veins widely sejiarated above. 

 Second sul)niarginal cell more than twice longer than the 

 third ; metathorax without a depression at base ; entirely 

 black parvula n. sp. 



Second submarginal not twice longer than the third ; metathorax 

 with a transverse depression at base ; abdomen, except first 

 segment, ferruginous rufiventris />/. 



Tachysphex apicalis 



; . — Medial portion of clypeus convex, with tolerably strong and close punc- 

 tures, before its anterior which is slightly emarginate medially, there is a wide, 

 transverse depression or furrow, extending from side to side and giving the anterior 



