Miscellaneous. 67 



sible to me ; but, having spoken above as if tbe opposite sex of P. 

 Castor were perfectly well known to naturalists, while, according 

 to Prof. Westwood, it is stiU undiscovered, I ought perhaps to say a 

 few words about the material on which my remarks are based. 



Fapilio Castor is restricted in its distribution to the slopes and 

 valleys of the hill-ranges of North-Eastern India and to the parts 

 of the plains in immediate contiguity to them, its place being 

 taken elsewhere, as in Southern India, by the new species described 

 in the preceding pages, and in Burmah by P. Mahadeva. The 

 Indian Museum possesses specimens from the southern slopes of the 

 Khasi hills (Silhet), from the Sikkim hills (Darjiling), Cherra Punji 

 in the Khasi hills, and the Naga hills ; and three males were taken 

 by Lieut. -Colonel Godwin-Austen during the Dafla expedition ; in 

 these last, in a large male from Cherra Punji, and in two specimens 

 of the same sex from the Naga hills, the upper surface is dark brown, 

 of a much lighter tint than in nine males recently received from 

 Sikkim (two) and Silhet (seven), which are aU brown-black of so 

 dark a shade as to appear quite black except when a strong light 

 falls upon them, when their colour appears brownish ; in fact tlje 

 brown of the former is to that of the latter series of specimens what 

 dark green is to the colour known as " invisible green." In the 

 large Cherra-Punji specimen the short tooth, or rudimentary tail, 

 into which the third branch of the median vein of the hind wing is 

 usually produced, does not extend beyond the line of the other lobes 

 of the outer margin ; and one of the three dwarfed winter speci- 

 mens* captured by Colonel Austen approaches it in this respect; 

 moreover one of the Silhet specimens has this tooth smaller in one 

 wing than in the other ; so that this, like secondary sexual charac- 

 ters in general, is subject to variation. It is possibly to difference 

 of station, but probably to long exposure to the vicissitudes of the 

 Calcutta climate, and to the application of benzine and other noxi- 

 ous substances to which they were subjected before I took over the 

 charge of the collection of Lepidoptera, that these brown specimens 

 owe their lighter coloration. However this may be, it may confi- 

 dently be asserted that it would be impossible for the most invete- 

 rate si)ecies-maker to discover any character by which to separate 

 them as a distinct species or race from the fresh and consequently 

 dark Sikkim and Silhet specimens. So much for the males. 



Of the nine females in the collection referred by me to P. Castor, 

 seven, being perfect, can readily be divided into two sets, according 

 to the form of the outer margin of the hind wing : — three (one from 

 Assam, one from Cherra Punji f, and a large one from Silhet) 



* The insect figured by Westwood (Arcana Entom. vol. ii. pi. 80. 

 fig. 2^ seems to have been a similarly dwarfed and faded individual. 



t There is another specimen from Cherra Punji (the largest of all in 

 the collection), with the outer margins of its hind wings so ragged that it 

 is impossible to he quite sure to which form it belongs, though, from its 

 close agreement in other respects with Westwood's figure in the ' Arcaua,' 

 as well as with the other insect from the same locality, I should say it 

 is a typical P. Pollux. 



