iv] NEW-WORLD MIMICS 39 



Castnia and Pericopis, are among the well-known 

 mimics of this group of models. The models themselves 

 are very variable in appearance. In one locality the 

 predominant pattern is black with a warm red-brown 

 diagonal bar occupying rather more than a third of 

 the fore wing (PI. XV, fig. 5), in another it consists 

 of parallel bands of black and fulvous brown with clear 

 yellow patches at the tips of the fore wings (cf. PI. X, 

 fig. 7), while in yet another locality it is different again. 

 Different localities often have their own peculiar pattern 

 and this affects the various mimics as well as the 

 Ithomiine and Heliconine models. 



These groups of different species, some belonging 

 to palatable and some to unpalatable groups, all 

 exhibiting a close resemblance in colour and pattern, 

 are far more strikingly developed in S. America than 

 in either Asia or Africa, and it is not uncommon 

 for eight or ten species to enter into such an association. 

 A group of this sort which possesses unusual interest 

 is the so-called "Transparency Group" from certain 

 parts of the Amazon region. It was originally de- 

 scribed by Bates with seven species belonging to six 

 different genera. To-day it is said that no less than 

 28 species of this peculiar facies are known, though 

 some are excessively rare. The majority are Itho- 

 miines, but two species of the Danaine genus Ituna, 

 the Pierine DismorpMa orise (PI. XII, fig. 2), the 

 Swallow-tail Papilio hahneli, and several species of 

 diurnal moths belonging to different families (cf. 

 PI. XII, fig. 4) also enter into the combination. 



