106 HTMENOPTERA OF AMERICA. [PART I. 



but truncate before, narrower than the 2d segment : its superior 

 face lengthened trapezoidal, offering at times a trace of a longi- 

 tudinal groove ; the suture distinct, placed on the anterior fourth 

 of the segment, but clearly separating the anterior and superior 

 faces. Second segment prolonged, slightly retracted at its base ; 

 its surface cribrose with great, slightly separated, punctures, 

 more crowded toward the posterior extremity ; the following 

 segments finely punctured. Border of the 2d segment not chan- 

 nelled. 



Insect black, with some gray reflections. Antenna? ferrugi- 

 nous beneath. A dot on the front, an edging ornamenting the 

 anterior and the posterior border of the prothorax, a line on each 

 side on the ridges of the metathorax, the anterior border of the 

 post-scutel and a spot beneath the wing, whitish, or pale-fawn 

 color. Posterior border of abdominal segments 1 and 2 orna- 

 mented by a whitish cordon ; that of the 2d segment very slender. 

 Knees and tarsi slightly ferruginous. "Wings hyaline or washed 

 with brown. Tcgnla? bordered with ferruginous; their appendix 

 very wide, squamiform, yellow. 



Var. Two spots or yellow lines on the summit of the clypeus. 



%. Abdomen more rugose, also more of venter; the 2d seg- 

 ment more swelled, and more compressed at its base ; no little 

 excavation on the vertex. Clypeus prolonged, terminated by 

 two blunt teeth, whitish; the carina of the front, the scape 

 beneath, and a line bordering the orbit as far as the bottom of 

 the sinus, whitish. Antennae fawn-colored beneath, with the last 

 articles black ; the hook black, lengthened and arcuate. 



Bess. a. cliff. — This species is very remarkable in the structure 

 of its metathorax. It approaches in its form to Symmorphus, 

 the first segment being narrower than the second and campanu- 

 late, and the metathorax being truncate as in the Symmorphus ; 

 but it belongs distinctly to the subgenus Ancistrocerus, as is 

 evident from the absence of the distinct dividing groove of the 

 first abdominal segment, the cylindrical form of the thorax, the 

 prothorax not retracted, the kind of punctures, the pyriform 

 clypeus, and the presence of a large hook on the antennas of the 

 male; the raesothorax offers no more longitudinal grooves; the 

 post-scutel is not rugose, nor the 2d segment smooth as with the 

 Symmorphus. It has quite the form of the 0. incommodus, but 



