202 Zoology of Colorado 



on the scutellum, back of the broad black band across the thorax. 

 This is deeply incised or even divided into two spots, whereas in 

 B. huntii the whole scutellum is covered with tawny hair. The 

 second species was named by Cresson Bombus bifarius; it is so 

 closely related to a Californian one that some authors regard it as 

 a local race or variety. Still another red-banded mountain bee 

 has the hair on scutellum and abdomen after the fashion of B. 

 huntii, but the hair of the face is almost black, whereas it is fulvous 

 yellow in B. huntii. This black faced insect, which has a rather 

 short, heart-shaped abdomen, is Cresson's Bombus rufocinctus. 

 It is one of the most variable of bees, and we often find the variety 

 astragali, in which the broad band across the abdomen is black 

 instead of red. There is an intermediate variety iridis, with the 

 band black, mixed with coppery-red hairs. The form with the 

 hair on the second and third abdominal segments entirely deep 

 red, the opposite extreme from astragali, is called var. phaceliae. 



There are two species of less robust bumble-bees, frequently 

 found at rather high altitudes, in which the red band is on seg- 

 ments three and four, instead of two and three. Of these, B. 

 juxtus has the yellow of the thorax above without black inter- 

 mixed, whereas there is a strong intermixture of black in B. flavi- 

 frons. The latter is especially found at high altitudes. 



Among the species without red hair, B. appositus is especially 

 known by the white hair on the anterior part of the thorax, before 

 the black band. B. americanorum, very common in the foothills, 

 is a large bee with the thorax black, the anterior part broadly 

 fulvous-haired ; the abdomen fulvous with the apex broadly black. 

 Another very common lowland species is B. fervidus, the thorax 

 above with a black band between the wings, the abdomen with 

 the first four segments yellow-haired. One of our most handsome 

 forms is the large B. morrisoni of Cresson, with no black band 

 between the wings; the abdomen with the yellow hair covering 

 the first two segments and part of third; the lower edge of the 

 yellow strongly convex. It is named after H. K. Morrison, who 

 explored the western mountains years ago, and discovered many 

 new insects. 



(3) Anthidium belongs to the Megachilidae, and has a 

 ventral scopa in the females. The abdomen and other parts are 

 marked with yellow, in a pretty pattern; it is especially to be 



