This bumblebee is one of the easier cuckoo bees to identify as females have a black body with two dusky yellow thoracic bands and a yellow-brown tail. Males are similar but with longer antennae and the colouration of the tail usually extends further up the abdomen. The wings are dusky and it lacks pollen baskets. The amount of yellow colouration is highly variable however and occasionally completely black melanic forms can be seen. It is stated that the primary host is Bombus pascuroum but that related other species like B. muscorum and B. ruderarius may also be used. It is rather scarce and is classed as Vulnerable.

Distribution in Ireland: Widespread but very uncommon and absent from large areas of eastern Ireland.

Flight Period: April-October, with males appearing in July.

Habitat: A variety of habitats are used, but contemporary Irish records are mostly from species-rich grasslands, limestone pavement and heathland.

Flowers visited: Dandelion, vetches, thistles, scabiouses and others.

Personal Records: I have found males of this species in dry heath on Furnish Island (Co. Galway) where both light and dark forms were present and feeding on Devil’s-bit Scabious. Both Bombus pascuorum and B. muscorum are present here, with the former appearing in large numbers. I have also encountered it in the Blackdown Hills in Devon, UK.