186 HTMENOPTEEA OF AMERICA. [PART I. 



pressed at the base of the second segment, the middle of segments 

 1st, 2d generally black, the red less developed. Legs often varied 

 with yellow. 



Far. The middle of the prothorax a little yellow. The black 

 enci'oaching upon the red. The scutels often black, bordered 

 with red ; the metathorax also often wholly black; the sculpture 

 of this last appears also to vary somewhat; at times the red is 

 more developed. Metathorax red ; flanks varied with red. 



Ress. a. diff. — Various Odynerus, properly speaking, are often 

 identical in color with this. Such are the 0. Morelise and Guer- 

 reri, but they may be sufficiently distinguished from it by the 

 absence of the tubercle on the vertex and of the suture upon the 

 ! -i gment. 



The 0. tuberculiceps hardly differs from the. 0. Sutterianus, 

 but by a less brilliant livery and by its prothorax slightly retracted 

 and angles less salient. 



Hab. The temperate regions and the plateau of Mexico. I 

 have found tin's Odynerus common in the most various localities. 

 In the eastern Cordillera; in the valleys of Orizaba and of Jalapa, 

 of bvero; in the Sierra Madre ; in the valley of Mextillan ; in 

 Huasteca on the Pacific slope, and in the province of Mechoaean, 

 aboul Morelia, Tuxpan, Zinapecuaro, Patzcuaro, and finally on 

 the plateau in the valley of Mexico. 1G 9, IS %. 



'Z"$. A. SislteriaiidS ». sp. — Niger, 0. tuberculicipiti simillimus; ver- 

 tice tubei'Culato, pronoto valde biangulato ; abdominis secundi segrnenti 

 margins canal iculato, rugoso, reflexo ; antenuis aurantiis, apice supra 

 nigri.s ; ore, dypeo, fascia post-on ulari, frontis macula et lineolis 4, 

 pronoto antice ; tegulis, macula subalnri, post-scutello, maculis 2 scu- 

 telli, tibiis tarsisque, sulfnreis ; abdomine sulfureo, seguaentis lo, 20, 

 basi nigris ; alia ferrugiueis, apice griseis. 



Total length, 12 mm. ; wing, 10 mm. 



9. Form and punctures exactly like those of the 0. tubercu- 

 liceps; clypeus pyrit'onn. finely bidentate. The same tubercle 

 on the vertex, appearing like a fourth ocellus, but the prothorax 

 not retracted before, more square; the angles alone very salient, 

 diverging and prolonged, perhaps bluntly terminated, not Conning 

 a sharp spine; the abdomen a little more slender; the margin 

 of the 2d segment a little less strongly upturned; the border of 



