1883.] MR. F. MOORE ON LIMNAINA AND EUPLOEINA. 205 



found in the jSIalay peninsula. These are arranged under the five 

 genera Hestia, Ideopsis, Radena, Danuis, and Euploea, the two latter 

 genera being further separated into sections, founded upon the 

 "sexual mark" of the male. 



The last work to be enumerated is the ' Lepidoptera of India, 

 Burmah, and Ceylon,' published at Calcutta in 1882, by Major 

 Marshall and L. de Niceville. These authors give copious details 

 of the characters of the subfamily Danainse, keys for the determi- 

 nation of the genera and species, and very ample descriptions of the 

 several genera and species, which are also accompanied with notes 

 on their habits and geographical distribution, together with some 

 exceedingly well-executed figures. By these authors the Danaiase 

 are divided into the four genera Hestia, Ideopsis, Danais, and 

 Euploea, the two latter genera being sectionized into named groups, 

 which are based on the " sexual mark " in the males, as pointed 

 out and named by Mr. Butler and myself. 



When studying this subfamily of Butterflies in 18/9, preparatory 

 to describing the species for my work on the Lepidoptera of Ceylon, 

 I separated the whole of the species then in my collection into groups, 

 according to the presence and position of the "sexual mark" or 

 " scent-producing organ " in the male insect. Having thus separated 

 the species into such groups, I was then much surprised to observe 

 that this operation had placed before me several species in each group 

 which bore an extraordinary resemblance, in the pattern of the mark- 

 ings on the wings, to certain species which i had arranged in the 

 other groups. 



Having thus taken these " sexual marks " or, as they are now 

 known to be, " scent-producing organs " as the primary structural 

 character for separating the species of the old genus Danais and 

 Euplcea into minor generic groups, these assemblies of species, thus 

 grouped, brought to my mind at once the fact that here were evident 

 illustrations of a form of mimicry occurring between closely related 

 groups, and that, too, within a protected family of Butterflies, or, 

 more extraordinary still, between species of the same genera, as it 

 would then appear, if the species are restricted to Danais and Euploea 

 respectively. 



At that time I had forgotten that this phenomenon of mimicry 

 between related genera had been observed by my friend Mr. Bates 

 among the Danaoid Helicouidae ; but subsequently, on again working 

 with his memoir in the Linnean ' Transactions ' before me, I became 

 aware of his discovery. 



This analogous form of mimicry, occurring in Danais and 

 Euploea, had, however, not previously been recorded. Certain 

 species, it is true, when being described, were noted by Mr. Butler 

 as having a resemblance to certain other isolated species. 



Since my own observations were thus made, I have had the 

 opportunity of showing and pointing out some of these mimetic 

 groups in Euploea to my friends Mr. Bates, Mr. Meldola, Mr, 



