AMERICAN HYMENOPTERA. 187 



Abdomen black and ferruginous. 

 Apex of abdomen black. 

 Scutellum black; posterior legs entirely black; abdominal segmenta 



two and three entirely ferruginous 17. riifizoiiatilS. 



Scutellum pale; posterior legs black, base of tibise ferruginous. 



AntenniB with short, thick-set joints; abdominal segments 2 and 3 



entirely ferruginous, apioal segments immaculate 19. Taos. 



Antennse with basal joints of flagellura elongate, cylindrical; abdomi- 

 nal segments two to four and apex of one, ferruginous, apical 



segments with pale spots 21. Nortoni, 



Apex of abdomen ferruginous. 

 Head and thorax black or blue. 

 Posterior legs entirely black. 



Postpetiole aciculated; joint 3 of antennse much longer than 4. 



Thorax deep black 22. <Ietritus. 



Thorax steel-blue 23. semiccerulens. 



Postpetiole scabrous; third and fourth joints of antennae equal in 



length 24. indistiiictns. 



Posterior legs more or less ferruginous. 

 Wings fuliginous; scutellum flat, entirely black; antennce without 



pale annulus 25. liutl«$oiiicns. 



Wings hyaline; scutellum convex, with white spot; antennae with 



pale annulus 28. coloradciisis. 



Head and thorax more or less ferruginous. 

 Abdomen broad, fusiform. 



Antennae with basal joints of flagellum (except first which is twice 

 longer than broad), quadrate or moniliform; thorax beneath 

 and metathorax generally black; abdomen generally entirely 

 ferruginous except base of first and occasionally base of two or 



three following segments 29. ^^iibriirns. 



Antennae with basal joints of flagellum (except first which is threo 

 times longer than broad), scarcely twice longer than broad; 

 thorax generally ferruginous with black sutures; abdominal seg- 

 ments generally more or less black at base 30. sutiiralis. 



Antennae with basal joints of flagellum long, cylindrical, more than 



twice longer than broad 31. subfui^eus. 



Abdomen narrow, subcompressed at tip. 



Antennae with pale annulus 32. ancops. 



Antennae without pale annulus 33. liiulcus. 



Metathorax with two prominent spines; thorax black and white; legs fer- 

 ruginous; antennae long, black with broad white annulus. 



Abdomen black, apical margin of segments white 34. ? c*<»iiciiiiiii{$. 



Abdomen ferruginous, with pale spot at sides of three basal segments. 



35. ? ornatuii. 



MALES. 

 Abdomen black or blue, immaculate above. 

 Legs black or blue and white. 



Scutellum and entire body blue-black 2. montanus. 



Scutellum pale. 



Face entirely black 6. expuiictus. 



