322 AMERICAN HYMENOPTERA. 



Variation. — This is one of the most constant species in 

 all its characters. The ferruginous pile on the second and 

 third dorsal abdominal segments has a considerable ten- 

 dency to fade out into yellow, and this has led to the females 

 having been sometimes labelled '^ Bonibus fervidus^^ in col- 

 lections. 



Habitat. — This species ranges through Washington, Idaho, 

 Montana, Oregon, Wyoming, California (except probably 

 their Lower Austral portions), Nevada, Utah, Colorado and 

 a considerable portion of New Mexico. It also occurs in 

 western Nebraska, western South Dakota, probably in west- 

 ern North Dakota and parts of Arizona and possibly in the 

 extreme western portions of Oklahoma and Texas. I have 

 records of it from Canada as follows : Vancouver Island, 

 British Columbia (Fort Macleod), Alberta (Macleod) and the 

 old territory of Assiniboia (Regina). What are its most 

 northern and eastern limits in Canada ? My most southern 

 record is Mescaleri, New Mexico. The species belongs 

 mainly to the Transition Zone, but it runs over somewhat 

 into the Canadian on one side and the Upper Austral on the 

 other. In certain parts of its habitat it is the most common 

 species present, especially so in Colorado. 



This species is most closely allied to B. edwardsii, from 

 which it can always be separated by the black corbicular 

 fringes of the females and by the straight hind border of the 

 interalar band. Its next closest ally seems to be B. vos- 

 nesenskiiy from which it is at once separated by its coloration. 

 It is a little more distantly related to B ternarius, from which 

 it is easily separable by means of its yellow face and occiput 

 and longer malar space, also by the more completely black 

 legs and the straight hind margin of the interalar band of 

 its females. The volsellae are more slender than those of 

 the ternarius male and the flagellum of the male antennae 

 does not appear crenate below, when viewed laterally, as it 

 does in that species. It is also closely allied to sylvicola, but 

 it has much shorter pile than does that species. 



This is the species which has long passed in the West as 

 B. ternariiis Say, but true ternarius is not present in any of 

 the Pacific States. 



