ITS HYMENOPTERA OF AMERICA. [PART I. 



anteriorly ; the prothorax with a crested margin, its angles 

 dentiform, acute. Post-scutel very short, strongly truncate; its 

 posterior face flat, polished; its superior face rough, transverse; 

 its posterior ridge very finely crenulate, the middle with a very 

 small compressed tubercle. Metathorax coarsely cribrose, silky- 

 grayish, its hinder face widely excavated, as polished as the 

 posterior face of post-scutel, somewhat punctate, finely margined; 

 the margins forming behind the post-scutel two quite small erect 

 teetli (not easy to distinguish) ; no distinct lateral angles. 

 Abdomen slender, slightly depressed ; the first segment small, 

 shortly and quite sharply truncate anteriorly ; the suture elevated ; 

 its superior face short, rather strongly punctured ; 2d segment 

 not quite so strongly punctured, its hinder margin with a line of 

 punctures, the following segments densely punctured. 



Black; grayish-silky. Mandibles partly fulvous; antennae 

 ferruginous beneath, scape yellow beneath. Two dots on the 

 summit of clypeus, a frontal spot, and post-ocular line, pale yel- 

 low. Hinder margin of prothorax with a narrow luteous band ; 

 its angles, appendix of wing scale, a spot under the wing, an 

 interrupted fascia on scutel, a transverse line on the hinder face 

 of post-scutel, and two large maculaa on the hind face of meta- 

 thorax, pale yellow. The first two abdominal segments narrowly 

 margined with luteous. Intermediate femora with a luteous line. 

 Anterior tibiae and tarsi brown or ferruginous. Wings hyaline, 

 smoky, nerves and anterior margin of the apex fuscous ; the 2d 

 recurrent nerve falling nearly upon the 2d transverse cubital vein. 



Var. Anterior margin of prothorax also margined with luteous. 



Bess. a. diff. — This is quite a distinct species and a peculiar 

 type, making a sort of transition to Stenodynerus by its slender 

 form, and its punctate abdomen, having the 1st segment more 

 punctured than the second. The form of the scutel, post-scutel, 

 and metathorax is quite unusual, and the very coarsely punctured 

 thorax makes it at once distinguishable. 



Its livery much resembles that of the A. Fariasi, but it differs 

 from this in all its form and its punctures ; in the first segment 

 being very short and truncate, its superior face quite transverse; 

 the scutel truncate, not triangular; the punctures of thorax and 

 head being much coarser, etc. It has also a resemblance to 0. 

 (Stenodynerus) totonacus. 



