The corbiculate bees comprise four tribes, the advanced eusocial Apini and Meliponini, the primitively eusocial Bombini, and the solitary or communal Euglossini. Recovering a robust phylogeny for the four tribes is of considerable importance for understanding the evolution of eusociality, yet previous morphological and molecular studies reached strikingly different conclusions. We study an expanded data set consisting of 12 nuclear genes to explore lines of support for the molecular hypothesis. Results corroborate previous molecular studies; support increases as more genes are added. Across genes, support for the molecular hypothesis is positively correlated with the number of informative sites and the relative substitution rate. Phylogenetic signals supporting the molecular tree rest almost entirely upon synonymous changes at the first and third codon positions. We discuss possible future approaches for resolving the frustratingly persistent corbiculate bee controversy.