Bombus (Pyrobombus) flavifrons, Cresson 1863
|Pile of scutum and scutellum yellow and black mixed; pleura yellow.||Pile of face yellow with black.||Gastral terga 1 and 2 yellow, at least laterally; terga 3 black, sometimes yellow basally; terga 4, 5, 6 mostly black.|
It is very difficult to distinguish female B. flavifrons from B. sitkensis in the Olympia, Washington area. In other regions there is less difficulty. According to Stephen (1957), B. sitkensis females always have reddish pile on gastral terga five and six and they lack a median ridge on the hypopygium. Therefore, B. flavifrons females have dark hair on gastral terga five and six or they have a median ridge on their hypopygium.
|B. sitkensis||B. flavifrons|
|T5 and 6 with brownish red hairs||T5 and 6 with mostly dark hairs|
|Hypopygium without ridge||Hypopygium sometimes with ridge|
B. flavifrons is found in the Pacific Coast states from British Columbia to Southern California.
Last updated Tuesday, July 25, 2006, by Lisa Ferrier