3658 The Zoologist — August, 1873. 



immediately adjoining and above the ordinary discoidal cell, and extending 

 beyond it. The subcostal nervules are 'angulated and drawn together' by 

 the transverse nervule, quite as Mr. Murray describes in P. Clodius, and 



the additional cell is of the same size and 

 ^ ^ shape iu both hind wings. It is observable 

 yy^^ ^^^W that the true discoidal cell is not at all dis- 

 ,y^^'i(''^'/ / I torted, but of the normal size and form in 

 '^/ xX^-^-fi / / ^'^^^ hind wings. This interesting example 

 / /// / / / of P. Merope was taken by Mr. J. H. 

 ' / \ \ W Bowker on the Boolo Paver, a small tribu- 

 tary of the Tsomo, in Kaffraria Proper. 



"I have in another place (Trans. Linn. Soc, vol. xxvi. p. 501, note) 

 commented on the remarkable neuration of the Papilionidae, and pointed 

 out how the presence of more than one cell enclosed by anastomosing 

 uervures constitutes an indication of aflinity to the Heterocerous groups of 

 Lepidoptera ; and this indication acquires additional significance in view of 

 the interesting facts recorded by Mr. Murray respecting butterflies of this 

 family, and of the circumstance of the tendency to form additional wing-cells 

 finding such marked development in the specimen of P. Merope above 

 described. There can, I think, be little doubt that (as Mr. Murray suggests 

 iu reference to the pre-discoidal cell discovered in some examples of Thais 

 Polyxena, W. V.) these exceptional cases of neuration are referable to rever- 

 sion to ancestral characters, and point to a remote community of origin 

 between the Papilionidae and the higher Ileterocera. 



" In my discussion (/oc. cit., pp. 501-2) of this question of the position 

 of the Papilionida:', I overlooked Boisduval's account (Faune Ent. de 

 Madag., &c., pp. G and 113) of the larva of the splendid Urania Rhipheus, 

 or I should not have quoted Cerura as affording the onhj other instance 

 among the Lepidoptera of organs analogous to the Y-shaped tentacle of the 

 Papilionide caterpillars. Boisduval states particularly (on the authority of 

 Captain Sganzin, who reared a large number of the Urania) that the larva 

 of Rhipheus possesses, ' comme dans Ics Papilio,' ' deux comes retractiles, 

 roses, placees sur le premier anneau,' adding that it exserts them at will 

 ('fait sortir a volonte'). ^.r. Wallace, not only in his paper on Malayan 

 PapilionidfB (Trans. Linn. Soc, vol. xxv.), but more recently in his valuable 

 ' Contributions to the Theory of Natural Selection,' 2nd edit. 1871, has laid 

 such stress on the possession of the exsertible Y-shaped organ being, as the 

 exclusive character of Papilionide larvae, a sign of the highest development 

 of the Lepidoptei'ous Order, that the presence of an apparently identical 

 organ in the undoubtedly Heterocerous Urania is a fact most worthy of 

 special notice. 



" PS. — I add a line to say that I have just heard (94th April) that proof 

 of the species-identity of Papilio Merope and Ps. Cenea, Hippocoon and 



