Sex Characters of Larval Bees (Hymenoptera: Apoidea)

A structure diagnostic of the male sex was found on the 12th sternite of all species of larval bees studied; it usually took the form of a narrow transverse slit on the posterior part of the segment. Structures diagnostic of the female were found on the same area of most species, but they were less well denned. Other characters situated on the posterior ventral area of the abdomen also were found useful in distinguishing the sexes of certain species. Differences between genera and species suggest the potential usefulness of these characters in taxonomic studies of larval Hymenoptera. Determination of sex by external structures was verified by waiting for pupation and by dissecting for the gonadal rudiments.