148 J. Wood-Mason — On a new Papilio from South India, [No. 3, 



from Chen-a Punji,* and a large one from Silhet) having the third branch 

 {d.^, pi. viii, fig. 2) of the median vein not produced and the outer margin 

 of the wing consequently ' rounder,' being, in fact, typical P. Pollux — 

 and four (two from Silhetf and two from Sikkim;]:) having that veinlet 

 produced into a small tooth (J.^, pi. ix, tig. 2) as in the male. I consider 

 that these two diffei'ent forms are both females of P. Castor, and that the 

 slight differences they present are explained on the supposition, warranted by 

 numerous analogous facts in nature, that the secondary sexual characters ac- 

 quired by the male have been partially transmitted to some females but not to 

 others (P. Pollux), which have retained the primordial rounded form of wing.* 



The fact that the discoidal markings of the hind- wing in the two Silhet 

 females with toothed wings are lighter and more distinctly cream-coloured 

 than in any of the females with rounded wings ; that the malformed speci- 

 men fi-om the same locality (which certainly belongs to the form with toothed 

 hind-wings) has these markings in the fourth, fifth, and sixth interspaces, 

 those, that is to say, corres23onding to the ones forming the principal part 

 of tlie blotch in the male, of almost as rich and pure a colour as in that sex ; 

 and that one of the two former has the spot at the end of the cell and the 

 subraarginal markings of both fore-wings obsolete and is thus still further 

 aj^proximated to the male ; do certainly seem to me to tell rather for than 

 against the above supposition. 



The PLelenus-^xow^ of Papilios, to which Papilio Castor and its allies 



* There is anotlier specimen from Cherra Punji, the largest of all in the collec- 

 tion, with the outer margins of its hind wings so ragged that it is impossible to be 

 quite sure to which form it belongs, though, from its close agreement in other respects 

 with Westwood's figure in the ' Arcana' as well as with the other insect from the 

 same locality, I should say it is a tyi^ical P. FoUux. 



t There is a third specimen from Silhet in the collection, taken at the same time 

 and place as the other two, but it unfortunately has the hind-wings symmetrically mal- 

 formed at theu' outer margins, the third lobule on each side being short and angulated 

 and the fourth being somewhat longer than usual and also angulated. This malformation 

 is interesting as showing in the same specimen the instability of this character, the 

 strong tendency to the assumption of the male form of wing exhibited in the lengthen- 

 ing of the lobule next in order, and the unmistakable ' reversion' to the rounded 

 form of wing in the suppression of the rudimentary tail. 



It should be mentioned that a gynandromorphous example of the form of female 

 described by Prof. Westwood as P. Pollux has been figured and described as P. 

 C«««o>- by Gr. Semper in Wien. Entom. Monatschr. 1863, Band vii, p. 281, Taf. 19. 

 In this specimen both the wings of the left side are truly female, but on the opposite 

 side the posterior portion of the fore-wing from the first discoidal veinlet to the inner 

 margin on the upper side only, and the anterior portion of the hind-wing from the 

 costal margin to the second branch of the sub-costal on both sides, exhibit the mascuHne 

 livery not unmingled with female characters [Conf. Westwood in Thes. Ent. Oxon. 

 p. 187). 



X The two Sikkim specimens have the tooth less developed and the discal mark- 

 ings of the huid- wings exactly like those of the other form (P. PolluxJ. 



