250 MR. G. E. DOBSON ON SECONDARY SEXUAL [Mar. 4, 



to a distinct species, R. perniger, Hodgs. ; others are black, sprinkled 

 with silvery grey, and must therefore, according to the same 

 authority, be relegated to a distinct species. But the closest exami- 

 nation fails to detect any structural difference other than sexual 

 between these specimens from Darjeeling. The " reddish leaf-nosed 

 Bat " of Fitzinger, R. eudouxii, Laplace, from the Philippine Islands, 

 is most probably the male R. luclus, its brighter colour dependiug on 

 locality, and perhaps, in a less degree, on season. 



In the Journ. As. Soc. Beng. vol. xli. p. 220, I have shown the 

 identity of Phyllorhina fulva, Gray, with P. murina, Gray, and 

 P. cineracea, Blyth, and have expressed my belief that P. atra et 

 atrata, which differ from P. fulva also only in the colour of the fur, 

 are referable to the same species. Later, in the Proc. As. Soc. Beng., 

 Aug. 1871, p. 155, I have remarked that the rich golden hue 

 of the fur of some specimens of P. fulva depends most probably 

 on sex and season, seeing that, of several specimens possessing this 

 golden colour examined by me, all were females and each contained 

 a more or less developed foetus. In the same paper I have adduced 

 evidence which now satisfies me that this golden colour is only 

 possessed by the females, and by them only under certain circum- 

 stances, as when in the pregnant condition. 



Mr. Blytb, who, in common with other zoologists, regarded the 

 golden-coloured specimens of P. fulva as representing a species 

 distinct from the white and black specimens, writes as follows : — 

 " This is perhaps the most vividly coloured of the whole class of 

 Mammalia; at least I know of no species which can at all compete 

 with it for brilliancy of hue. The colour of the fur is here alluded 

 to ; for that of the naked skin of the Mandrill and of certain Cerco- 

 pitheci can scarcely be surpassed. The general tint of the fur is 

 splendidly bright ferruginous, that of the upper parts being slightly 

 tipped with a darker shade ; membranes dusky." To this Mr. Blyth 

 adds: — "Inhabits Southern India, where very rare"*. 



The comparative rarity of the golden- coloured specimens is easily 

 explained when we know that this colour is only possessed by the 

 females of P. fulva, and by them only under certain conditions. 



I believe the same change occurs in the breeding-season among 

 the females of Nycticeius lemminckii, Horsf., the commonest Bat 

 about Calcutta. The usual colour of this Bat is pale straw-colour 

 on the under surface, sometimes almost white. This colour 1 have 

 observed in male and female specimens from all parts of India ; hut 

 in females obtained in the months of March and April I found the 

 prevailing hue to be rich saffron-colour, exceeding that of the 

 Canary bird. 



Among the Frugivorous Bats the same rule appears to hold good, 

 that the females are always darker in colour than the males of the 

 same age. This I have constantly observed in Pteropus medius, Temm. 

 Also in a Pteropus from the Andamans f and Nicobars the females 



* Journ. As. Sue. Bong. vol. xiii. p. 489. 



t Distinguished by the form and size of its ears from JY. medius and other 

 allied species, probably Ft. nicobaricus, Schriezer, Novara Expedition. The first 



