The ovarian oil injection and ovariolar separation techniques were applied to determine the
physiological age of species of the 3 dipteran families Culicidae, Simuliidae, and Tabanidae. The presence
of a granular basal body (a granular area in the calyx wall within the ovariolar sheath) indicates at least 1
egg laying; that is, it can be used to separate parous from nulliparous females, which possess no granular
basal body. In parous females, the number of ovipositions can be determined accurately by counting the
number of dilatations in the diagnostic ovarioles. An egg sac, when present, indicates only the current egg
laying. A diagram for age grading using the technique is presented and discussed.
