CALLIDRYAS. 
121 
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 dif- 
ficult to determine. They inhabit the intertropical 
regions of the tuo continents. 
