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 two continents. 



