The role of juvenile hormone (JH) and corazonin in the maternal regulation of progeny characteristics was examined in the migratory locust, Locusta migratoria (Orthoptera: Acrididae). Crowded female adults are known to produce large eggs, heavier and darker hatchlings than solitarious female adults which produce smaller eggs, smaller hatchlings with brighter cuticular colour. Implantation of corpora allata (CA) taken from gregarious sexually mature females caused crowded females to deposit smaller eggs and smaller, lighter hatchlings. The neuropeptide [His⁷]-corazonin, present in the central nervous system and corpus cardiacum, is known to induce darkening of body colouration when injected into locusts reared in isolation. To examine whether this neuropeptide is responsible for the maternal regulation of progeny phase characteristics, 1 nmol [His⁷]-corazonin mixed with 2 µl of sunflower oil were injected twice into solitarious female adults. No effect of corazonin on egg size, the weight of the hatchlings and brightness of their cuticular colour changes was found.