MOEPHOLOGY OF THE LEPIDOPTERA. 173 



But the most curious feature in the developmental history of the Lepidopteran azygos 

 oviduct is the distinct evidence it affords of the fact that it is divisible into sections 

 which must have been successively acquired in the phylogeny of the order. Up to the 

 last stage of active existence the female caterpillar may be said to exist, so far as its 

 genitalia are concerned, in an embryonic condition, one which is persistent only in 

 female Ephemeridce among living insects, as has been shown by Palmen, ' Ueber paarige 

 Ausfiirhungsgange der Geschlechtsorgane bei Insecten,' Leipzig, 1884. The ovaries 

 and the paired oviducts are alone present, and the latter end ventrally near the posterior 

 edge of the seventh abdominal somite. Were they sexually mature, this is the exact 

 state of things found by Palmen in the female imago of the Mayflies. The prolonged 

 embryonic condition of the parts as they exist in the caterpillar, clearly shows, among 

 other things, that the larva of the Lepidoptera is a specialized form. The next step is 

 the appearance of the rudiments of the accessory organs, and then of a fold on either 

 side of the common rudiment of the bursa and receptaculum. The two folds approach 

 one another ventrally ; their edges do not fuse, however, and before they do so the first 

 section of the azygos oviduct is established and is in connection, solid connection it is 

 true, with the paired oviducts. The first section may therefore be considered as the 

 homologue of the vagiua in other Insecta. The condition now established is very 

 similar to what is found in sexually mature Orthoptera, using that term in the signification 

 to which it is limited by F. Brauer, in his " Systematisch-Zoologischen Studien " (Sitzb. 

 Akad. Wien, xci. Abth. 1, 1885, p. 358), to include only the Orthoptera vera of other 

 authors, minus the Forficulidce. In Blatta a short vagina, the uterus, so-called by 

 Nussbaum, connects the paired oviducts to the exterior ; it opens on the eighth sternum. 

 The spermatheca opens behind the vaginal aperture on the ninth sternum and the 

 colleterial or the sebaceous glands still further behind. The same arrangement obtains 

 in the Acrididce and Trxuvalidce according to Berlese (Atti Accad. dei Lyncei (3), Memo- 

 rie, xi. 1881, p. 273), but in the Mantidce, Locustidce, and GryllidcB the spermatheca 

 opens into the dorsal wall of the vagina — in other words, the latter is of greater length 

 (Berlese, op. cit. pp. 271-273). The middle section of the azygos oviduct of Vanessa 

 persists for some time as an open furrow, and the third section, the last formed, is a 

 furrow in direct continuity with it, extending backwards as far as the base of the 

 sebaceous apparatus. The conversion of the whole furrow into a tube does not take 

 place until pupation is at hand ; and when its closure occurs it leaves two openings, an 

 anterior and a posterior, a peculiarity of the Lepidoptera, and one that clearly stamps, 

 from the phylogenetic point of view, the middle and especially the third section of the 

 oviduct as later acquired structures *. 



Of the two apertures in question the anterior or bursal must be considered as the 



* Doyere stated, in the Annales des Sc. Nat. (2), vii. 1837, pp. 203-205, that in the Cicada there is a vestibule 

 into which opens anteriorly the azygos oviduct, and dorsally tho spermatheca ; it opens itself posteriorly into the base 

 of the ovipositor, and ventrally behind the ovipositor. I have no means of verifying the fact myself, and de Lacaze- 

 Duthiers throws no light on it in his paper on the composition of the ovipositor in the CicadiJce (Annales des Sc. 

 Nat. (3), xviii. 1852, p. 339 et seqq.). No later authority seems to have written on the subject. 



