This faded male bumblebee is, I believe, Barbut’s Cuckoo Bee. This species resembles its host, Garden Bumblebee (Bombus hortorum), but has an almost circular face, unlike the elongated face of Bombus hortorum. As a cuckoo bee, the female searches out a nest of its host bumblebee, entering the nest, usually killing the host queen, then laying its eggs in the nest. The cuckoo bees larvae are then fed and looked after by the host worker bees until they leave the nest in July - September.