Stop the presses! As of July 29, 2020 Washington state has a new bumble bee species. Genetic analysis has determined that the population of the Two form bumble bee, Bombus bifarius in British Columbia has been recognized as a new, separate species. This new species is the Vancouver bumble bee, Bombus vancouverensis. This includes the population located in the San Juan Islands. Ergo, we have a new species!
What is not clear is what the actual differences are between the Vancouver bumble bee and the Two form bumble bee. At first I (DJ) thought that the individuals showing red on T2 and T3 were vancouverensis and the ones with T2 and T3 black were bifarius. Now it appears separating the two species in Washington may be a bit more challenging. For now I am keeping the two species separate on this site, but be advised, they may be color morphs of the same species (B. vancouverensis)
Field ID Tips
Range, range, range. Within Washington state, this species is restricted to the area around the San Juan Islands. It has a similar color pattern to the Two Form bumble bee. It shows an inverted black triangle on the scutellum. T1 & T4 are yellow. T2 and T3 show a lot of red. T2 may show a black notch.
The red morph of the Yellow head bumble bee, which is also located in the San Juans, is somewhat similar, but it show red on T3 and T4. The Yellow head bumble bee also lacks an inverted black triangle.
The Black tail bumble bee shows red in the middle of the abdomen. T4 is black with a white line of hairs, no inverted black triangle.