The egg and mature larva of a presently unnamed species of the bee genus Plebeia are anatomically described, illustrated, and compared with those of other known Meliponini, based on abundant specimens collected from two nests recovered from a tree at the Yasuní Scientific Station, Orellana Province, Ecuador. A key to the four tribes (Apini, Bombini, Euglossini, and Meliponini) of known mature corbiculate larvae is then presented. It, in turn, is followed by a preliminary larval description of the Meliponini based on those taxa the mature larvae of which are known so far. The main feature distinguishing the mature larva of the Meliponini is in its having a tapering slender elongate mandibular apex, which contrasts with the much shorter, robust mandibular apex of the other three tribes. Furthermore, unlike in the other tribes, late stage larval Meliponini possess paired dorsolateral tubercles on most abdominal segments.