on Eastern Butterflies. 287 



above the other, at the anal angle in Cramer's figure, but 

 only one in all the specimens of D. anomala. Now in all 

 these points in which the figure dijBFers from D. anomala, 

 it agrees pretty closely with some of the female forms of 

 D. Lasinassa, to which I have little doubt it belongs. 



Biadema anomala offers the most remarkable case 

 known among butterflies of a reversal of the usual sexual 

 colouring, the males being always dull brown, the females 

 glossed with rich blue. The reason for this exception to 

 the ordinary rule is, I believe, to be found in the fact 

 that the brilliant blue gloss causes the female to resemble 

 or mimic the Euploea Midamus, one of the very common- 

 est butterflies of the East, and one that belongs to the 

 pre-eminently protected group of the Danaidve. The two 

 insects frequent the same places, and the resemblance on 

 the wing was such as to deceive myself, and it is perhaps 

 owing to this cause that I captured so few specimens of 

 this interesting butterfly. That protection which female 

 insects usually obtain by being less brilliant and con- 

 spicuous than the males, is here given by exactly oppo- 

 site means ; a remarkable proof, as it appears to me, that 

 female butterflies would be more generally brilliant than 

 they are, were not their variations in this direction 

 checked, and eliminated by the danger they incur through 

 it. It may be observed, that in the allied species Biade- 

 ma Antilope, the female resembles Eujyloea Climena (a 

 common species in the countries it inhabits) much more 

 than the male does. It also closely resembles Elymnias 

 Vitellia, a species which has long figured in our lists as a 

 Biadema; and there is reason to believe that the Eury- 

 telidce, to which Elymnias belongs, are themselves a pro- 

 tected group, though perhaps not so perfectly so as the 

 Banaidce. 



I exhibited this species at the British Association in 

 1866, as a remarkable illustration of '^mimicry,'' and 

 afterwards at a meeting of this Society; and I should 

 have described the species before, had I not for a long 

 time considered with Felder, that it was a form of Peri' 

 mele. 



16. Diadem A albula, n. s. 



Form of B. anomala, rather smaller. 



Male. Above; rusty brown, the markings as in B. 



