260 



RHOPALOCERA MALAYANA. 



mar-in • first subcostal nervule omitted at about one-third from base, and terminating on costa a little 

 beyond end of cell, second emitted about midway between first and third, the last of which arises at about 

 an equal interval from end of cell, third and fourth bifurcating at about middle or two-thirds of third; 

 first and second median nervules about one-third nearer together than second and third, the first convexly 

 rounded. Posterior wings broad, the costal and outer margins convex, with a short tail-like appendage 

 at apex of third median nervule, either distinct as in N. cc,itauru.% or short, fragile, and obscure as in 

 N amphimata ■ anal an-le obliquely rounded and not lobed. Costal nervure about reaching apex of wmg ; 

 subcostal nervules bifurcating at about one-third before end of cell ; first and second median nervules 

 emitted somewhat close together near end of cell ; lower median nervule at about one-third before end of 

 cell. Body robust ; palpi porrect, second joint compressed and flattened. Antennae very slightly and 

 gradually thickened at apex. 



I have failed to find any structural differences between the two genera Narathura and 

 Nilascra, as proposed by Mr. Moore, and, although the first and earliest name is here used, 

 it is not without some hesitation, as no single character of neuration is given in the diagnosis 

 of Narathura, and it can only be accurately determined by the fact of the typical species 

 {Ambhjpodia hjpomuta, Hewits.) being given. 



This genus and the two following, Panchala and Amhbjpodia, have till quite recently been 

 classed and catalogued together as one genus under the last-mentioned name. As, at present, 

 all the species thus treated have not been examined to ascertain their true generic position, it 

 will be better to deal with them corporately in ascertaining their geographical distribution. This 

 distribution is distinctly Oriental, and not only includes Continental India, the neighbouring 

 islands, and the Malay Peninsula, but also the entire length and breadth of the Malayan 

 Archipelago. 



Another strongly marked peculiarity of these genera is their singular individuality, both 

 in depth and intensity of hue and general increase of size, compared with the remaining 

 Ljicmnida;, which affords some support to the theory that climate has a tendency to influence 

 coloration. This principle can of course have no universal application, as in the Tropics 

 we find no diminution of pale-coloured butterflies. The true test seems to be this, whether we 

 can observe, in difierent groups, that the most melanic members of those groups are found in 

 the region of the Tropics, whilst at the same time the most albinic species are discovered only 

 in the highest latitudes to which the distribution of the group extends.* The whole question, 

 however, still requires a further amount of material and a patient and qualified investigation. 



One other feature of this deep blue coloration is not to be neglected, and that is its 

 recurrent character throughout the Khopalocera. In families whose members have a generally 

 sombre hue it usually appears in an unexpected, complete and brilliant manner, and in 



* Ml-, de Vismcs Kane has recently aihocateil this view as the result of his study of European Lepidoptera 

 (•Naturalist,' Nov. 1884, p. 77). The result of other investigations has pointed to similar considerations, m which, however, 

 tlie controlling or exciting cause has heen rather that of soutliern latitude than of tropical heat. Thus Prof. Milne-Edwards 

 pursued a course of studies on the colour of hirds as connected with their geograpliical distrihution, and found that birds 

 with black plumage are found in almost all parts of the world ; but in certain widely distributed families the tendency 

 to melanism is displayed only in the soutliern hemisphere, and especially in the oceanic district including New Zealand, 

 New Guinea, Madagascar, and the intermediate islands. This was remarkably illustrated in the family of swans, of which 

 its numerous representatives in the northern hemisphere are all perfectly white, whilst in the southern hemisphere there are 

 only three species, of which one, that of New Holland, is perfectly black, and of the two others, natives of South America, 

 one has a few black feathers and the other a black head and neck, the rest of the body being white (' Comptes Rendus,' 

 Dec. "29, 1873). This peculiarity has also been shown by Mr. J. A. Allen to exist in the North American birds (Proc. Bost. Soc. 

 Nat. Hist. vol. xv. p. '212), and also — and by the same naturalist — to be found in the North American squirrels (Paper read 

 before U.S. Soc. Nat. Hist. Boston, Feb. 4, 1874). - 



