Third instar larvae of the cotton boll weevil, Anthonomus grandis grandis (Boheman) (Coleoptera: Curculionidae) are offered to the parasitoid Jaliscoa grandis Burks, 1954 (=Catolaccus grandis) (Hymenoptera: Pteromalidae) for mass-rearing. Variations in the size of boll weevil larvae, produced on an artificial diet and reared in the laboratory, may be related to the luminosity of the environment. The objective of this study was to evaluate the development, survival, and morphometric parameters of cotton boll weevil larvae and pupae obtained from a rearing colony in the Entomology laboratory of Embrapa Algodão, fed an artificial diet under different photoperiods. The experimental design was completely randomized, with five treatments (photoperiods of 0:24, 10:14, 12:12, 14:10, and 24:0 (L:D)) and 260 replications. Each treatment consisted of 13 Petri dishes, with 20 boll weevil larvae per dish. The weight of boll weevil larvae and pupae and the duration of these stages were greater in the dark (00:24 hours) than in the other photoperiods (10:14 h, 12:12 h, 14:10 h, and 24:00 h), but survival was similar among photoperiods.