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Genus CALLIDRYAS. 



This genus is composed of a selection of species 

 from CoKas, to which it bears a very close relation. 

 It is not long since it was proposed by Dr Bois- 

 duval, who thinks that the following characters 

 entitle it to this distinction. Palpi approximating 

 and very much compressed, clothed with short hairs 

 and dense scales, the terminal joint conical and much 

 shorter than the preceding one ; antennae thickening 

 gradually from the base to the apex, which is dis- 

 tinctly truncated ; body robust, the abdomen much 

 shorter than the inferior wings ; the latter forming 

 a groove which completely embraces the under side 

 of the abdomen. The caterpillars are naked and 

 somewhat attenuated at both extremities ; the chry- 

 salis arched, or boat shaped, with the extremities 

 drawn out to a narrow point ; always attached by 

 the tail and a transverse band. 



According to the manner in which they have 

 been respectively constituted, Callidryas therefore 

 is best distinguished from Colias by the antennae, 

 which in the latter terminate in an obconical club ; 

 and from Rhodocera (including Gonopteryx of Dr. 

 Leach), which has these organs likewise truncated, 

 by the shape of the wings, which never present acute 

 angular projections. The prevailing colour of the 



