[5] Female B. sonorus is recognized by having the thoracic hairs yellow on the pronotum, anterior portion of scutum, and scutellum resulting in a black band between the base of the wings.

[4] It is known to collect pollen from Gossypium, Viguiera, Helianthus, Linaria, Chrysothamnus, and Kallstroemia flowers.

However, the common name has always been the Sonoran bumble bee--likely due to an incorrect translation of sonorus and propagation of that error.

If the species name had intended to refer to the Mexican state of Sonora (or the Sonoran desert), it would have been sonorensis.

B. sonorus occurs from California to central Texas and south to southern Mexico.