204 ME. E. B. POULTON ON THE EXTEENAL 



supporting other observations which prove that these parts are respectively homologous. The 

 external reproductive organs are seen obliquely, and therefore indistinctly in this and the last 

 figure. 

 Fig. 11. x-f. The last three abdominal segments of a male pupa, seen from the ventral aspect. The 

 male opening is distinct on the ninth abdominal segment ; its direction is somewhat oblique, 

 an irregularity which is not uncommon and probably follows from the extremely ancestral 

 character of the organs. The lateral lips are flattened and marked with a sculpture which is 

 different from that of the surface of the ninth abdominal segment. The anal cushions are of 

 normal size, and serve as a gauge of the amount of abnormality of figs. 8, 9, and 10 in this 

 respect. 



Figs. 12-14. The Terminal Abdominal Segments of the Pupa of Smerinthus tiliee. 



Fig. 12. Natural size. The last four abdominal segments of a female pupa, seen from the ventral aspect. 



The median prolongation of the tenth abdominal is distinct, and the median slit in front of its 



apex represents one or both generative openings. 

 Fig. 13. Natural size. The last five abdominal segments of a male pupa, seen from the left side. The 



scar of the caudal horn is distinctly seen in profile. The generative organs cannot be seen, 



but the contour of the ventral part of the terminal segments is characteristic of the male 



sex. 

 Fig. 14. Natural size. The last three segments of a pupa (sex unnoted), seen from the dorsal aspect, in 



order to show the scar of the caudal horu from above. 



Figs. 15-19. The Terminal Abdominal Segments of the Pupa of Acherontia ah'opos. 



Fig. 15. x 9. The median ventral part of the last three segments of a female pupa. Both generative 

 openings are distinctly visible in this individual ; the opening of the oviducts is large and sur- 

 rounded by a thickened V-shaped lip. It is placed in front of the apex of the median prolon- 

 gation from the tenth abdominal, and appears to be clearly situated in an anterior median 

 extension of the ninth abdominal segment. The opening into the bursa copulatrix is imme- 

 diately in front of the other aperture, but separated from it by the boundary between the 

 eighth and ninth abdominal segments. The opening extends forward as a narrow median slit 

 as far as the anterior boundary of the eighth abdominal. The anus (A) is distinct on the 

 tenth abdominal. The sculpture on the surface of the pupa and the various wrinkles &c. are 

 carefully copied in the figure. These details required for their elucidation the most careful 

 examination of an especially favourable individual in a very strong light. The general resem- 

 blance of the generative apertures to those of a well-marked individual of Cossus ligniperda 

 is very striking (compare figs. 27 and 29). 



Fig. 16. Natural size. The last three segments of a female pupa, seen from the ventral aspect. The 

 generative apertures could not be made out without magnification, but the median prolongation 

 was very distinct, far more so than in the last figure. In front of the anus (A), at the base of 

 the median prolongation, there is the deceptive appearance of an opening with lips, due to 

 wrinkles in the pupal case. The true generative openings never assume so posterior a position. 

 In fig. 15 the true nature of the marking is apparent. 



Fig. 17. x 9. The median ventral area of the ninth and the anterior part of the tenth abdominal seg- 

 ments of a male pupa. The figure hardly needs description as the male organs are quite 

 typical. The lateral tubercles are roundish and somewhat flattened. The sculpture of the 

 surface is represented. The exact relation of the male organ to the boundary between the 

 ninth and tenth abdominal segments varies greatly in different species (compare figs. 11, 20, 

 21, 23). 



