4 AMERICAN HYMKNOPTERA. 



Antennte as long, or slijihtly longer tlian head and thorax, sculpture of mid- 

 dle segment coarsely rugoso-reticulate. the enclosure about as usual; 

 head above closely punctured inixtiis. 



8. Dorsulum coarsely striato-punctate 9. 



Dorsnlum otherwise sculptured 10. 



9. Flagellum thick, reddish basally. nodose beneath from joint 3 Kolllii. 



Flagellum slender, not reddish, not nodose simpIicicoriii!>i. 



10. Ocelli forming a curved line, the space between hind pair much greater than 



that between them and eyes (a recurrent vein received by the second 



and third submarginal cells) tibialifS. 



* Ocelli forming a triangle, the space between hind pair never much more than 

 equaling that between them and eyes 11. 



11. Second and third submarginal cells each receiving a recurrent vein ; abdo- 



men, antennae and most of legs reddish inoiilicola. 



Second submarginal cell receiving both recurrent veins 12. 



12. Antennae slender, long, scarcely thickened apically argeiitifron*«. 



Antennae shorter, more or less clavate 13. 



13. Petiole of abdomen distinctly longer than hind femur; flagellum short, 



strongly clavate, the basal joint rather distinctly dentate beneath. 



Cressonii. 

 Petiole of abdomen not longer than hind femur 14. 



14. Petiole of abdomen flat above, not convex: head strongly and closely punctured. 



bai^iriifus. 

 Petiole of abdomen rounded or convex above • • -15. 



15. Petiole of abdomen as long as. or neai'ly as long as hind femur 16. 



Petiole shorter than hind femur 17. 



1(5. Antennae as long as head and thorax borealis. 



Antennte stouter, shorter than head and tharax pauper. 



17. Abdomen elongate, clavate, Trypoxylon-Wke ; enclosure of middle segment 



closely granulate granulosus. 



Abdomen otherwise shaped 18^ 



18. Legs more or less testaceous 20. 



Legs entirely black 19. 



19. Petiole about half as long as hind femur ; second submarginal cell triangular, 



the first and second transverso-cubital veins uniting above -grejisari us. 



Petiole nearly two-thirds as long as hind femur; second submarginal cell with 



the transverso-cubital veins separated above pro.Yiiiia ? 



20. Abdomen entirely black, shining; length 8 mm. or over niaculipes. 



Abdomen more or less red ; length under 6 mm 21. 



21. Middle segment coarsely rugoso-reticulate: antennae rather stout and clavate, 



stouter than head and thorax, entirely testaceous: legs testaceous; ab- 

 domen short and ovate cingiilatus. 



Middle segment rugose, but not reticulate; antennae slenderer, less clavate. 

 as long as head and thorax, pale beneath toward apex ; tibiae and tarsi 

 more or less testaceous: abdomen slender, elongate unituiictus. 



1. Group frontalis {=Psemdus Kohl.) 



1. I*seii frontalis n. sp. 



9. — Head with strong, separated punctures: front between antennae with a 

 strong production or prominence which extends up in the form of a carina, and 



