MORPHOLOGY OF THE LEPIDOPTEKA. 149 



account be also misplaces or misdescribes the positions of the apertures in the two 

 sexes, though the particular figures to which he refers his readers appear to bear out 

 his words. But others of his figures are more correct than his account ; e. g. Taf. xiv. 

 figs. 4>p 2 , 4<p d , and Taf. xvi. figs. \p, 2p,3p, which show the male aperture in the 

 segment in front of the anal segment, and the female (confluent) aperture as situated 

 apparently in the centre of the eighth segment, i. e. the segment in front of the one in 

 which the male aperture occurs. 



Dr. Haase also remarks to me that the sexes of the Lepidopteran chrysalid have been 

 " long known to all practical Lepidopterists." This may be the case in Germany, but 

 it is certainly not so in England, so far as concerns the sexual apertures of the pupa. 

 Before my paper was read I consulted Professor Westwood and several other practical 

 Lepidopterists, who assured me to the contrary. Moreover, except on the, assumption 

 of ignorance, it is hard to account for tbe complete silence of text-books in general on 

 the subject. 



§ 2. Development of the Azygos Oviduct and its accessory Organs in Vanessa Io. 



It is a well-known peculiarity of the Lepidoptera that the female ducts have two 

 external apertures. The only exception known to me is Nematois metallicus, described 

 by Cholodkowsky in the ' Zeitschrift fur wiss. Zool. ' xlii. 1885. Prom his account I 

 gather that there is only one aperture in this Micro-Lepidopteran, and that one the posterior 

 of the two usual apertures. All the Macro-Lepidoptera which have been examined 

 possess an aperture which leads into the bursa copulatrix, and is placed on the ventral 

 aspect of the eighth somite, and a second aperture which leads outwards fr^om the 

 oviduct and is placed ventrally to the anus, on the papilla that terminates the abdomen. 

 The aperture of the bursa is the one by which copulation is effected; the qviducal 

 aperture the one by which the ova are always laid. Pig. 19 on PL XV. sho\ws the 

 .•jizygos oviduct and accessory organs of Vanessa Io, the type 1 have investigated. \ It is 

 given more as a standard of reference for the developmental history than for any pther 

 purpose. The four ovarioles, cut short, are to be seen on each side (ov., ov.) ; they; are 

 attached to the ends of the paired oviducts (od., od.) which in their turn enter the azygos 

 oviduct (od') *. This tube terminates by an aperture just below the rectum (r). The 

 accessory organs appended to the azygos oviduct are, in order from before backward, a 

 " seminal canal " (s.c), leading to the bursa copulatrix (b.c), a receptaculum seminis 

 (r.s.\ and a pair of sebaceous glands (s.gl.), with a common duct (d.s.gl.). Imme- 

 diately below the termination of the azygos oviduct is a pan* of glands supposed to be 

 odoriferous by von Siebold. The left one alone is visible (od.gl.). The seminal canal 

 (s.c), it may be noted, opens on the dorsal aspect of the azygos oviduct. It is somewhat 



* Four ovarioles on each side is the number typical of Lepidoptera. The only known exceptions are mentioned 

 by Cholodkowsky, in his paper cited in the text (op. cit. p. 500). They are the following : — Psyche helix with six on 

 each side (A. Brandt), Sesia scoliiformis with fourteen (E. Brandt), and Xematois metallicus with twelve (one 

 specimen), sixteen (one specimen), eighteen (two specimens), and twenty (six specimens). 



