species is yellow, from deep orange to the palest sulphur yellow. The females are usually of a paler hue than the males, and the sexual differences are strongly marked in other particulars. On the under side of the wings there are almost invariably one or two small spots, near the middle, of a silvery or rusty-brown hue; these are either wanting or very minute in the males, while they are distinctly marked in the females. The former sex, in the majority of species, presents a very peculiar character in having the anterior edge of the under wings provided with a kind of pulverulent glandular sac, which varies much in size and colour in different species.
A great similarity prevails among the different species of Callidryas, and they are consequently difficult to determine. They inhabit the intertropical regions of the two continents.
