Female Bombus distinguendus (Great yellow bumblebee)
A female specimen of Bombus distinguendus © P Williams
Key characteristics of the female of Bombus distinguendus
Within Britain, Bombus distinguendus queens and workers are easily distinctive because of their combination of large size, extensively yellow hair, and black band between the wing bases. They have a body length of 12-21mm.
However, there are many other similar looking species around the world (Williams, 2007). Therefore, outside Britain, many detailed characteristics need to be checked:
Head
- Clypeus shining, in its central half lacking medium or large punctures, with only a few widely scattered micropunctures
Hair
- Mid basitarsus with the longest hairs of the posterior margin as long as or longer than the greatest breadth of the basitarsus
- The longest hair near the posterior margin of metasomal tergum 5 about 1.5× as long as the greatest breadth of the hind basitarsus
Colour pattern
- Head hair is often predominantly yellow, but variable, with at least some yellow hair intermixed on the vertex posterior to the ocelli.
- Dorsum of the thorax and of the metasoma is predominantly straw yellow, paler posteriorly.
- Tergum 2 is always yellow, with at most a few inconspicuous anterior black hairs (cf. B. subterraneus).
- Black hair forms a band between the wing bases, although usually with yellow hair strongly intermixed in a lateral longitudinal band next to the tegula.
- Legs distally and tergum 6 predominantly black, although the extent of the black on the metasoma is variable, sometimes with black hair intermixed on terga 1-5 anteriorly, and especially broadly on tergum 5, although this black hair rarely forming conspicuous black bands
- Sometimes has black hair intermixed on terga 1-5 anteriorly, and especially broadly on tergum 5, although this black hair rarely forms conspicuous black bands.
- Ventral surface varies from entirely grey-cream to almost entirely black.