AMERICAN HYMENOPTERA. 135 



Antennsfi short, with thick-set joints. 



Posterior femora and tibiae black at tips; antennae with white annulus; 



scutellum yellowish 183. viciiiH!^. 



Posterior legs entirely ferruginous; antennae without pale annulus; 



scutellum ferruginous 184. brcvipciinis. 



Abdomen with large black mark on disc of segments two and three, apical 



segment with pale spot 188. disparilJS. 



Abdomen entirely ferruginous. 



Metathorax with two prominent, flattened tubercles 201. riitilus. 



Metathora.x without prominent tubercles. 



Postpetiole densely and finely scabrous; antennae robust, with short, 



thick-set joints ISO. riissatus. 



Postpetiole distinctly aciculate 160. instabilis, var. 



Postpetiole either smooth, or indistinctly aciculated. 

 Antennae entirely ferruginous. 



Size medium ; antennal joints elongate 190. MCiniSi^liS. 



Size small ; antennal joints short 200. petiilciis. 



Antennae with pale annulus. 



Second segment of abdomen impunctured 193. proxiinus. 



Second segment closely and finely punctured; posterior tibire pale at 



base, fuscous at tip : thorax varied with dusky. ..194. iiJinilM. 



Second segment of abdomen coarsely punctured; body and legs 



entirely ferruginous 195. riibicuuduit. 



Postpetiole distinctly punctured. 

 Clypeus very short and broad, its anterior margin broadly arcuated, 



exposing most of the mentum 190. rcfi^idiiui^. 



Clypeus of usual proportions, its anterior margin truncate, covering 

 the mentum 198. soror. 



MALES. 

 In the following table, which will serve to distinguish the males, 

 those of the species belonging to Ambli/teles (of the division ainldij- 

 pi/'ji) are included, it being difficult and often impossible to separate 

 them from the males of Ichneumon, the ventral fold sometimes varying 

 considerably in length in specimens of the same species. 



Abdomen black or blue, without pale bands or sjiots, except sometimes on apex 



of first or last segments .' Section I. 



Abdomen black spotted or banded with white beyond first segment and before 



apex Section II. 



Abdomen black and yellow, sometimes varied with ferruginous Section III. 



Abdomen fulvo-ferruginous, apical margins of segments 1 — 4, and terminal 



segment pale yellow Section IV. 



Abdomen bright saffron-yellow, the three or four apical segments black; lega 



entirely yellow Section V. 



Abdomen more or less ferruginous or fulvous, apex always black Section VI. 



Abdomen ferruginous or fulvous, the first and base or apex of two or three 

 following segments more or less black, apex never black Section VII. 



