[ 187 ] 



V. The External Morpliology of the Lepidopterous Pupa : its Belation to that of the 

 other Stages and to the Origin and Sistorij of Metamorphosis. — Parts I.-III. By 

 Ebwaed B. Poulton, M.A., F.B.S., F.L.S., of Kehle and Jesus Colleges, Oxford. 



(Plates XX. & XXI.) 



Eead 21st N ovcmber, 1889. 



Contents. 



Page 



iNTHODrcTioN. — The Xames of the various Appendages itc. of the Pupa. — A Classification of 

 the various Features constituting the External Morphology of the Pupa. — Conclusions 



as to the Nature of Lepidopterous Metamorphosis 187 



Pakt I. — The persistent Traces of Larval Structures upon the Pupa. 



1. The Claspers 192 



2. The Caudal Horn of Sphingida; &c 192 



3. Other Larval Structures which can be detected on the Pupa 192 



4. Larval Tufts of Hairs indicated on the Pupa 193 



.5. Larval Markings upon the Pupa 193 



Part II. — The Number of Abdominal Segments and their Relation to those of the Larva. 



1 . The Number of Abdominal Segments in the Larva 195 



2. The Eelation of the Terminal Abdominal Segments of the Pupa to those of the 



Larva 195 



Pari III. — The External Reproductive Organs. 



1. Introductory and Historical 197 



2. The Male External Reproductive Organs 199 



3. The Female External Reproductive Organs 200 



IKTBODUCTION. — The observations recorded in this paper and those which will 

 follow it were begnn in the autumn of 1883, and have been continued intermittently up 

 to the present date. The remarkably characteristic form of the external generative 

 organs in both sexes of the pupse of several British Sphingidaj first directed my attention 

 to the subject. Por a long time I hoped that it would be possible to bring out a 

 monograph dealing with the whole question. The length of time which must have 

 elapsed before anything like a complete treatise could have been produced, and the diffi- 

 culties attending the only suitable form of publication, as a quarto volume, have induced 

 me to take the advice long ago offered by Prof. E. Ray Lankester, and to bring out a 

 series of papers dealing successively with the various morphological features which can 

 be detected on the surface of the Lepidopterous pupa. 



In the meantime my friend Mr. W. Hatchett Jackson, Deputy Linacre Professor of 

 Human and Comparative Anatomy in the University of Oxford, has also been studying 



SECOND SERIES. — ZOOLOGY, VOL. V. 29 



