The Osirini are a tribe of cleptoparasitic apid

Apidae

The Apidae are a large family of bees, comprising the common honey bees, stingless bees , carpenter bees, orchid bees, cuckoo bees, bumblebees, and various other less well-known groups...

 bees, all but one genus exclusively from the Neotropics, and laying their eggs in the nests of bees in the apid

Apidae

The Apidae are a large family of bees, comprising the common honey bees, stingless bees , carpenter bees, orchid bees, cuckoo bees, bumblebees, and various other less well-known groups...

 tribe Tapinotaspidini; the one exceptional genus is Epeoloides

Epeoloides

Epeoloides is a genus of cleptoparasitic bees which lay their eggs in the nests of melittid bees of the genus Macropis.Consists of two species:*Epeoloides coecutiens Fabricius, 1775*Epeoloides pilosulus...

, which has one North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

n species and one Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

an species, both of which attack the melittid

Melittidae

The family Melittidae is a small bee family, with some 60 species in 4 genera, restricted to Africa and the northern temperate zone. Historically, the family has included the Dasypodaidae and Meganomiidae as subfamilies, but recent molecular studies indicate that Melittidae was paraphyletic, so...

 genus Macropis

Macropis

Macropis is a genus of bees.-Description:Apoidea are of moderate size, not exceeding 15 mm. They have a livery predominantly black, males are characterized by conspicuous yellow markings on the head , but the females show morphological adaptations related to their foraging habits of flower oils,...

.

All species in this tribe are unique among the bee

Bee

Bees are flying insects closely related to wasps and ants, and are known for their role in pollination and for producing honey and beeswax. Bees are a monophyletic lineage within the superfamily Apoidea, presently classified by the unranked taxon name Anthophila...

s in the possession of a tiny sclerite

Sclerite

A sclerite is a hardened body part. The term is used in various branches of biology for various structures including hardened portions of sponges, but it is most commonly used for the hardened portions of arthropod exoskeletons....

embedded in the membrane beneath the head, possibly to help guard against being stung in the neck by an angry host bee when invading a nest.