We describe the egg, three instars, and pupa of Dacus bivittatus Bigot using optical and scanning electron microscopy and compare them with those of other Dacus Fabricius species for which these stages have been described as well as those of two important pest species of Zeugodacus Hendel that infest cucurbits. A new anatomical term, lateral lips, is introduced to describe a feature of the facial mask. A feature of the egg that has not been reported previously for Tephritidae is described here: a peculiar arrangement of aeropyles in an irregular line partially encircling the egg near the posterior end. A table of morphological characters visible with light microscopes provides diagnostic information to separate larvae of Dacus bivittatus from those of most other Dacus species and two Zeugodacus species for which larvae have been described.