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IV. Studies in the Morphology of the Lepidoptera.- — Part I. By W. Hatchett 

 Jackson, M.A., F.B.S., Deputy Linacre Professor of Anatomy in the University 

 of Oxford. 



(Plates XV.-XIX.) 



Bead 21st November, 1889. 



JL HE present paper represents a portion of an investigation which was begun some 

 years ago but was laid aside at the time for want of material ; its resumption was 

 prevented by the claims of other and very pressing duties until the summer of the 

 present year. The results obtained are now laid before the Society in the hope that they 

 may prove of interest, and as a first contribution from studies which still remain to be 

 finished. There are, however, one or two points in this first portion which will require 

 some further elucidation ; but as a year must elapse before the necessary specimens can 

 be procured, it seems to me that it is better not to keep back what has been done, 

 especially as the points in question are not of critical importance. 



Two subjects are here dealt with. The first is the external anatomical marks by 

 means of which the sex of a chrysalis may be determined ; the second, the mode in 

 which the azygos oviduct or vagina of the female butterfly with its accessory organs 

 develops between the close of larval life and the assumption of the state of the imago *. 



§ 1. The External Anatomical Characters distinctive of Sex in the 

 Lepidopteran Chrysalis. 



After a search of some extent in the literature which deals with the anatomy of the 

 Lepidoptera, I have come to the conclusion that none of the many authorities who have 

 studied this order of Insecta have ever noticed the fact that the sex of every chrysalis is 

 denoted by fixed anatomical characters f. Yet such is the case. If the dorsal aspect of 

 a chrysalis is carefully examined, it will be seen at once that there are thirteen somites 

 following the head, three thoracic, and ten abdominal, the last somite carrying the 

 cremaster, which represents the anal valve of the caterpillar. The eighth somite, which 

 has a particular connection with the object of this section, may be identified at once for 



* A preliminary account of the results of this investigation was sent to the ' Zoologischer Anzeiger ' on Oct. 7, 

 and appeared in No. 322 of that periodical for Dec. 2nd, 1S89. 



t II}- search in this connection has extended through the works of Kirby and Spence, Burmeister, Wcstwood, 

 Camerano, Graber, Scudder, and various anatomists, as well as writers of special monographs such as Lyonet, 

 Herold, and Suckow. Figures occur hero and there in which the markings distinctive of sex are more or less 

 clearly indicated, but their import has not been recognized. See Addendum, p. 148, post, and Zool. Anz. Jan. 27. 1S90. 



SECOND SERIES. — ZOOLOGY, VOL. V. 23 



