THE BUTTERFLIES OF CEYLON. 85 



leads up to the question of so-called " wet " and " dry " seasonal forms 

 and the causes thereof. 



There is no doubt that with the curious exception of certain species 

 of Pierince the " wet " season form is invariably darker than the " dry." 

 Specimens of many species which do not produce marked seasonal forms 

 if caught in the rains show a depth of colouring which is absent in 

 " dry " weather (Le., Cynthia). 



