Bombus sylvarum Linnaeus, 1761

Bombus sylvarum is a medium-small size. (Females: 16-18 mm; males: 12-14 mm)

Female: small size, with a long head. Conspicuous clypeus, longer than wider with a thin and dense stipple. Shiny forehead, with unspotted zones well defined. On the hind legs, convex tibia, without crosslinked appearance. Genitalia with external projections of the stinge's case wide, the internal ones also are wide.
Yellow colour, with a grey-green tone in most of the body surface. Face, vertex and torax of a pale yellow-green colour. The last segments are red coloured. Legs with hair of a yellow-red colour.

Male: small size. Long head. It shows a jaw with beard long and dense. Clypeus thin dotted at the discus. Genitalia with hooked sagittae, without central black tooth. The coloration is similar to that of the females, with yellow and black stripes.