The relationships between colour phases, sexual maturity and age were studied, using capture-recapture, dissections and direct observations. All young individuals were found to have greenish-yellow background body colour, which darkened to brown in females and to black in males. All males had a blackish wing banding which darkened with age, although many females (about 63%) lacked it. When present, the wing band in females in brownish and in some individuals darkens with age. Full sexual maturity was recognised by the presence of spermatophores in the penis (males), or by the presence of sperm in the reproductive system (females). In males sexual maturity coincided with the development of the completely black body and heaviest wing banding. In females, sexual maturity was closely correlated with brown body colour, but no clear association could be detected between intensity of female wing banding and sexual maturity or age. The mean age of males at the onset of sexual maturity was about 11 days.