Red-tailed cuckoo bumblebee (Bombus rupestris)
A large red-tailed cuckoo bumblebee, with a big subquadrate head. Like all cuckoo bumblebees, this species does not collect pollen to feed offspring, but instead takes over nests of the Red-tailed bumblebee (Bombus lapidarius). Widespread but not particularly abundant across the south of the UK, the species has been increasing in abundance and spreading northwards in recent years.
Females are sparsely hairy and have very dark, almost black wings, unlike any similar species. Males have largely undarkened wings, but the indistinct greyish-yellow banding and lack of obvious yellow facial hair separates them from the Red-tailed bumblebee and Early bumblebee (Bombus pratorum). The male genital capsule is useful to check the ID, particularly of worn specimens.
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For more detailed information visit: http://www.bwars.com/index.php?q=bee/apidae/bombus-rupestris