The common _Danais chrysippus_ (Pl. IV, fig. 1), found in this region, has been described as probably the most abundant butterfly in the world, and serves {24} as a model for several species belonging to different groups. It and its mimics will, however, be described in more detail later on. Mention must also be made of the striking case of the Danaid, _Caduga tytia_ and its Papilionine mimic _P. agestor_ from Sikkim (Pl. II, figs. 2 and 3). In both species the fore wings are pale blue broken by black; while the hind wings are pale with a deep outer border of rusty red. Not only in colour but also in shape the swallow-tail bears a remarkable resemblance to the Danaid. _C. tytia_ is also mimicked by a rare Nymphaline _Neptis imitans_, which exhibits the same striking colour scheme so very different from that of most of its allies. No less remarkable are some of the cases in which the Euploeines serve as models. _E. rhadamanthus_, for example, is mimicked by the scarce _Papilio mendax_, and a glance at Figs. 8 and 9 on Plate II shews how well this butterfly deserves its name. _Euploea rhadamanthus_ also serves as a model for one of the several forms of female of the Nymphaline species _Euripus halitherses_. In some Euploeines the sexes are different in appearance--a somewhat unusual thing among butterflies serving as models in cases of mimetic resemblance. Such a difference is found in _Euploea mulciber_, the male being predominantly brown with a beautiful deep blue suffusion, while the female is a rather lighter insect with less of the blue suffusion and with hind wings streaked with lighter markings (Pl. II, figs. 4 and 5). It is interesting to find that _Elymnias malelas_, a Satyrid which mimics this species, {25} shews a similar difference in the two sexes (Pl. II, figs. 6 and 7). It is remarkable that similar sexual difference is also shewn by the rare _Papilio paradoxus_, the two sexes here again mimicking respectively the two sexes of _Euploea mulciber_. Many of the Euploeines, more especially those from Southern India and Ceylon, lack the blue suffusion, and are sombre brown insects somewhat relieved by lighter markings along the hinder border of the hind wings. _Euploea core_ (Pl. I, fig. 10), a very common insect, is typical of this group. A similar coloration is found in one of the forms of _Papilio clytia_ (Pl. I, fig. 8) from the same region as well as in the female of the Nymphaline species _Hypolimnas bolina_ (Pl. I, fig. 6). The male of this last species (Pl. I, fig. 5) is quite unlike its female, but is not unlike the male of the allied species, _H. misippus_, which it resembles in the very dark wings each with a white patch in the centre, the junction of light and dark being in each case marked by a beautiful purple-blue suffusion. There is also a species of _Elymnias_ (_E. singhala_) in this part of the world which in general colour scheme is not widely dissimilar from these brown Euploeas (Pl. I, fig. 9).