RUOPALOCERA MALAY AN A. 73 



followed by two more obscure and much straighter fascise, one submar^^inal and the; other marginal. Posterior 

 wings with three ocellated spots with white centres and whitish and l)lack margins, the upper and largest 

 of which is situate between the subcostal nervules, the second and smallest is placed between the lower 

 subcostal and discoidal nervules, and the tliird between the second and tliird median nervules. Both wings 

 have also a few whitish suffusions, and the anterior wings are shad(;d witii dark l)rown beyond the apex of 

 the cell, and become more or less fuscous beneath the second median nervule ; caudate prolongations 

 marked with w'hite on each side as above. The sexual tufts and margins of glands paler than wing. 



Body and legs more or less concolorous with wings. 



Female. Wings above pale brownish. Anterior wings becoming chocolate-brown beyond apex of 

 cell, and there possessing the following pale stramineous markings : — a waved fascia commencing on costal 

 margin a little beyond cell and terminating above first median nervule, where it is outwardly followed by a 

 small spot ; beneath arc six spots placed three above and tliree beneath the second median nervule ; and 

 near apex there is also an indication of a pale spot. Posterior wings with the outer marginal area more or 

 less ochraceous, on which is a submarginal waved and l)roken dark chocolate fascia, becoming in some 

 specimens (as the one figured) obsolete towards anal angle ; on inner side of this ochraceous area is an 

 ill-defined darker ajiical patch or suffusion, on which are tlu'ee pale ochraceous spots, two above and one 

 beneath the discoidal nervule ; there is also a similar but much fainter spot beneath the first median 

 nervule (in one Malaccan specimen now before me these spots are nearly obsolete) ; anal caudate prolongation 

 marked with white on each side. Wings beneath generally as in male, but the smaller ocellated spot on 

 posterior wings in male absent, and the whitish suffusion more distinct. 



Exp. wings, S 90 to 96 millim. ; 2 110 to 120 millim. 



Hab. — Malay Peninsula ; Province Wellesley (coll. Sailer) ; Malacca (Brit. Mus.) — Sumatra (Brit. 

 Mus.) — Borneo (coll. Godm. & Salv.). 



Z. ainethjstus does not probably extend north of the Malay Peninsula, as here faunistically 

 treated, as from Tenasserim a closely allied species has been described.* Considerable variation 

 in depth of coloration is observable both above and beneath amongst male specimens. 



This species affords a striking example of sexual dissimilarity in coloration and markings, 

 in explanation of which several theories have been advanced, which are at least suggestive, if 

 not conclusive. As in this case, where dissimilarity exists, it is usually, though not invariably, 

 the male which is the most showy and brightly coloured, and Mr. Darwin considers that this is 

 due to "sexual selection," or, in other words, "the females for many generations having 

 chosen and paired with the more attractive males," f and certainly much of the argument which 

 he applies to the sexes of the American genus Epkalia will apply to Zeiizidia. It is probable, 

 at least on this view, that the female form represents more or less the ancestral type of the 

 genus, for not only are all the female forms of Zcuzidia with which I am acquainted coloured in 

 this manner, but similar sexual forms occur in the American genus JSIorpho, of which a striking 

 example is the I'apilio mairits of Schaller, which, judging from the somewhat indifferent figure, 

 Mr. Kirby quite reasonably placed in the genus Zcuzidia, but which, by the acquisition of a 

 Guianan specimen, I was subsequently enabled to show was the female sex oi Jforpho adonis, I and 

 almost simultaneously Mon. C. Oberthiir ligured the closely allied female sex of Morplio eugenia.^ 

 We have already alluded to the natural affinities of these genera, and the geological evidences 

 which minimise their present geographical estrangement, and when we observe tliat in each 



^= Z. masoni, Moore. f ' Descent of Man,' 2nJ edit. p. 318. 



I Trans. Ent. Soc. 1881, p. ;!;)7. § ' Etudes d'entomologie,' liv. 6me, t. vi. f. 1. 



September 30, 1882. u 



