 The bumblebee tribe Bombini is one of four groups of corbiculate bees ( those with pollen baskets ) in the Apidae , the others being the Apini ( honeybees ) , Euglossini ( orchid bees ) , and Meliponini ( stingless bees ) . The corbiculate bees are a monophyletic group . Advanced eusocial behaviour appears to have evolved twice in the group , giving rise to controversy , now largely settled , as to the phylogenetic origins of the four tribes ; it had been supposed that eusocial behaviour had evolved only once , requiring the Apini to be close to the Meliponini , which they do not resemble . It is now thought that the Apini ( with advanced societies ) and Euglossini are closely related , while the primitively eusocial Bombini are close to the Meliponini , which have somewhat more advanced eusocial behaviour . Sophie Cardinal and Bryan Danforth comment that " While remarkable , a hypothesis of dual origins of advanced eusociality is congruent with early studies on corbiculate morphology and social behavior . " Their analysis , combining molecular , morphological and behavioural data , gives the following cladogram : 
