Bombus vestalis Bumblebee Bee Insect Hymenopterus Apidae

Bombus (Psithyrus) vestalis cm 1.4-1.5 Bumblebee Bee Insect Hymenopterus Apidae.
Common name: Vestal Cuckoo Bee.
Syn. Psithyrus vestalis.

Bombus vestalis (Geoffroy, 1785) is a hymenopteran insect of the Apidae family (subfamily Apinae, Bombini tribe).
Like other species of bumblebees, it is covered with thick down and has a livery of yellow, black and white bands. Females are larger than males (20-24 mm versus 15-19 mm) and lack the typical specialized pollen-collecting structures on their hind legs.
It is a species characterized by social parasitism: the females of B. vestalis lay their eggs among those of the congener Bombus terrestris, entrusting the burden of parental care to the workers of the host species. Being social parasites, they lack workers. It is the pollinator insect of two wild orchids of the Italian flora.
It has a Palearctic range that extends from central and southern Europe to Iran, going south to North Africa.
Together with the other species of parasitic bumblebees, B. vestalis was previously placed in a separate genus (Psithyrus); the current orientation is to consider Psithyrus as a subgenus of Bombus.