COLOR AND COLORATION 207 
vety black; the female smoky, with a white pterostigmatal 
spot. Among Coleoptera, the male of Hoplia trifasciata 1s 
erayish and the female reddish brown; a few more examples 
might be given, though sexual differences in coloration are 
Fic. 236. 
ToS 
Callosamia promethea; A, male, clinging to cocoon; B, female. Reduced. 
comparatively rare among beetles. Of Hymenoptera, some 
of the Tenthredinidz exhibit colorational antigeny. 
Among tropical butterflies there are not a few instances in 
which the special coloration of the female is adaptive—har- 
monizing with the surroundings or else imitating with remark- 
able precision the coloration of another species which is known 
