252 AMERICAN HYMENOPTERA. 



The scutellum covered with black pile or else a black interalar 

 band present 33 . 



31. Not more than two dorsal abdominal segments covered to any ex- 



tent with other than black pile 34. 



More than two abdominal segments covered entirely, or for the most 

 part, with other than black pile 35. 



32. First four abdominal segments entirely covered above with yellow 



pile fervidiis var. dorsalis. 



Not all of these segments covered with yellow pile 36. 



33. Apical abdominal segments with white pile above .....41. 



Apical abdominal segments without white pile above 44. 



34. Ocelli large ; well below the supra-orbital line, in the narrowest 



part of the front ; the lateral ones nearer to the margins of 



the eyes than to each other 39. 



Ocelli small ; near the supra-orbital line ; the lateral ones not 

 nearer to the margins of the eyes than to each other 40. 



35. First four dorsal abdominal segments entirely covered with yellow 



pile; the apical segments without ferruginous pile 57. 



Either not all the first four dorsal abdominal segments are covered 

 with yellow pile, or the apical segments bear considerable 

 ferruginous-red or yellowish ferruginous pile, or both 58. 



36. Only two abdominal segments with yellow pile above ; eastern. 



perplexus. 



More than two of the dorsal abdominal segments with yellow pile ; 



western 37. 



37. Malar space not longer than its width at the apex morrisoni. 



Malar space longer than its width at the apex 38. 



38. Ocelli placed well below the supra-orbital line, in the narrowest 



part of the front uevadensis. 



Ocelli placed near the supra-orbital line, above the narrowest part 

 of the front sonoriis. 



39. Black interalar band present ; malar space twice as wide at its 



apex as it is long fraternus. 



No black interalar band present ; malar space not twice as wide 

 at its apex as it is long 45. 



40. Malar space as long as, or longer than, it is wide at its apex 47. 



Malar space wider at apex than it is long 46. 



41. Some of the abdominal segments covered above with ferruginous- 



red pile sylvicola. 



None of the abdominal segments covered above with ferruginous 

 pile 42. 



42. Fringes of corbiculae with a distinct ferruginous tinge. 



occidentalis. 

 Fringes of corbiculas black, with little or no ferruginous tinge. ..43. 



43. First dorsal abdominal segment entirely covered with black pile ; 



second segment entirely covered above with yellow pile. 



terrestris var. inoderatus. 



