Reproductive cycles have been studied, in -the wild for many lizards, covering the temperate, sub-tropical and tropical zones. However, there are few reports of long term laboratory studies under standaxdized conditions of light and temperature. In addition, reports concemming the effects of environmental factors and their relative importance in reproduction are contradictory. In Chalcides ocellatus malesq the reproductive cycle has been studied by Badix and colleagues (Badir, 1955 & 1958; Badir & Hussein, 1964) who claimed that Optimal conditions of light and temperature could cause a complete shift from a cyclic to a "continuous" pattern of reproductive activity, though their claims do not appear to be justified. This thesis presents findings on the reproductive features of male Chalcides, under standardized conditions of light and temperature, some effects of daylength and temperature on reproduction, variations in plasma and testiculax androgen levels under a variety of photothermal conditions and a histochemical study of a ste=oidogenic enzyme in the testis of this lizard, all in an attempt to elucidate the pattern and controls of =ep=oductive activity.