Male Bombus distinguendus (Great yellow bumblebee)
A male specimen of Bombus distinguendus © P Williams
Key characteristics of the male of Bombus distinguendus
Within Britain, males can be distinguished from similar looking B. campestris and B. subterraneus by their genitalia, and by details of their colour pattern.
However, there are many other similar looking species around the world (Williams, 2007). Therefore, outside Britain, many detailed characteristics need to be checked:
Head
- The clypeus is nearly covered in dense, moderately long hair, except in a narrow median band occupying the median quarter in the anterior ventral quarter adjacent to the labrum.
- Hairs are longer than the breadth of the scape in the distal third.
Genitalia
- Gonocoxa with the proximal inner process shorter than broad, apically obliquely truncate.
- Gonocoxa with the sharply-defined dorsal ridge reaching the distal outer margin before the distal extremity, which is flat dorsally.
- Gonostylus broadly triangular, breadth of the inner proximal process about half of the length of the gonostylus.
- Volsella are distally narrowed.
- Penis valve with the ventro-lateral process almost trident-like, usually with only a weak dorsal tooth (cf. B. subterraneus), a strongPenis valve has an almost trident-like ventro-lateral process, with usually only a weak dorsal tooth (cf. B. subterraneus), a strong ventral tooth, and a rounded scarcely marked central projection.
- Penis valve head distally broadly rounded on its outer edge, its outer proximal corner with a flattened process reduced to a dorso-ventral ridge, dorsally with a small tooth and ventrally with a more triangular process.
Colour pattern
- Hair generally usually predominantly straw or lemon yellow, paler ventrally, usually with the majority of at least the shorter hairs just dorsal to the antenna base yellow (cf. B. subterraneus), except for a black band between the wing bases, although this black band usually has yellow hairs intermixed at least laterally next to the tegula and sometimes throughout.
- Legs distally and tergum 7 often predominantly black, and although the extent of the black on the metasoma is variable, tergum 2 without black hair (cf. B. subterraneus).