1889.] W. Bohevtj—Nofes on Assam Bidterflies. 121 



below, and but sliglitly clouded with wliitish and dirty yellow. It waa 

 usually taken in the forest, moving slowly about in the deep shade, or 

 lying perdue among the leaves. The other was almost as brightly 

 coloured with pure white and rich yellow as the male, difEering chiefly in 

 the absence of the subapical yellow spot on the forewing below. Like 

 the male it was always flitting up and down the sunny paths at the 

 edges of the wood, only alighting from time to time for a moment or 

 two. Intermediate specimens occurred, and there was no possibility 

 that the species could be different ; but the forms were so unlike that 

 they might almost claim to be called dimorphic. I might have hesi- 

 tated to adopt the conclusion that the differences corresponded with, 

 or perhaps resulted from, the difference in station and habits, if I had 

 not observed precisely the same thing in Appias nero in Borneo and 

 the Malay Peninsula. Here again a female almost as richly-coloured 

 as the male,* flies about with it in the sunlight, and a dusky, dull 

 orange form lies hidden in the woods. But it is possible that these 

 differences in the female may correspond with those very slight ones in 

 the male on which Mr. Butler has hasedi his Appias figulina, auA. ih&ii 

 two distinct species are in question. 



In Euthalia and its allies, great differences exist in allied species 

 in the costal vein of the forewing, which in some species is free, and in 

 some anastomosed with the first subcostal branch. I here give a list 

 of the species taken in Assam, and those in the Indian Museum, ar- 

 ranged with reference to this peculiarity : 



With the costal vein free, 

 Sijinplmdra nais, 

 Lexias tetda, 

 Lexias teiUoides, 

 Lexias recta, 



* TJiilegs my memory fails me, Mr. Forbes, in his " Wauderinga in the Eastern 

 Archipelago," observes that the females of Beleiiois, Catopsilia, Appias, and Helomoia 

 are more conspicuously coloured than the males. Seen against the white floor of a 

 cabinet-drawer, or against a dusty road, they may be, but white backgrounds are 

 not to be found in the jungle as nature made it. There the male of Appias nero 

 goes by like a flash of living Are, and the pure white of the male of Appias leis or 

 the green-white of the male of Catopsilia are of a brightness almost luminous. The 

 dark variegations of the female obviously mitigate their brilliancy. Besides, even 

 the brightest-hued females are more retiring and fonder of the shade than the 

 males are, and hence less obvious. In all probability the female is only more con- 

 spicuous than the male in such extraordinary species as that justly called HypoUmnas 

 onomaZa by Wallace, and perhaps iu a few such iycren idee as Biduanda thesmia and 

 Catapwcilma delicatuin. 

 16 



