MORPHOLOGY OF THE LEPIDOPTEROUS PUPA. 207 



are distinct ou the eighth and ninth abdominal segments. The rudimentary spiracle on the 

 former and the male organs on the latter are also seen. The division of the tenth abdominal 

 into a ventral (anal) and dorsal part is distinctly shown. Four small spines are placed on the 

 latter part, as in fig. 27. 

 Fig. 32. Natural size. The last five segments of the same pupa, as seen from the right side. The semi- 

 circles of hooks on the sixth, seventh, eighth, and ninth abdominal segments are distinctly 

 seen, together with the functional spiracles on the first two of these and the rudimentary 

 spiracle upon the eighth abdominal. Some slight irregularities of the surface below the spiracle 

 on the sixth abdominal represent the larval clasper. The two parts of the tenth abdominal 

 and its imperfect semicircle of spines are also seen, together with the male organs on the 

 ninth abdominal. 



Plate XXI. 



Figs. 1-23 represent Pupse of Heterocera; the remaining figures represent the 



Pupae of Rhopalocera. 



Figs. 1, 2. The Terminal Abdominal Segments of the Pupa of Zeuzera cesculi. 



Fig. 1. X 26. The median ventral area of the eighth, ninth, and the anterior part of the tenth abdominal 

 segment of a female pupa. The resemblance to the pupa of Cossus is very marked (compare 

 Plate XX. fig. 29), although the two reproductive openings are almost fused together. The 

 surface-sculpture is represented. The anterior prolongation of the tenth abdominal is very 

 distinct, as in Cossus, although in both these species its base is separated from the rest of the 

 segment by a well-marked line of demarcation and by a difference in the character of the 

 surface. 



Fig. 2. X 26. The median ventral area of the ninth and the anterior part of the tenth abdominal seg- 

 ment of a male pupa. The male organ is beautifully regular ; the lateral tubercles are some- 

 what flattened. The relation of the organ to the division between the ninth and tenth segments 

 is carefully figured. 



Figs. 3-6. The Terminal Abdominal Segments of the Pupa of Pygcera bucephala. 



Fig. 3. X 5*25. The last three segments of a female pupa seen from the ventral aspect. The median 

 prolongation of the tenth abdominal is unusually long, so that its apex and the incon- 

 spicuous opening of the oviducts is carried forward beyond the middle of the eighth abdominal : 

 the opening of the bursa copulatrix is distinct and has a thickened border. The anus (A) is 

 - small. The shape of the double terminal spine is remarkable. The rudimentary spiracles are 

 seen at the sides of the eighth abdominal. The surface-sculpture is represented. 



Fig. 4. Natural size. A representation of the same parts (except that the seventh abdominal is also 

 included) in another female pupa. The object of the figure is to prove that sexual characters 

 are easily distinguished by the naked eye. A characteristic feature is aftorded by the median 

 prolongation of the tenth abdominal. The female sexual openings are only distinctly seen in 

 the majority of individuals by means of a lens. 



Fig. 5. Natural size. The ninth, tenth, and the posterior part of the eighth abdominal segments of a male 

 pupa, seen from the ventral aspect. The male organs are seen to be distinctly recognizable 

 without magnification. They are characteristic in form and position. 



Fig. 6. Natural size. The same segments, as seen from the dorsal aspect. The object of the figure is 

 to show a structure which corresponds to the black plate upon the dorsal surface of the larval 

 anal flap. It is placed on the anterior dorsal margin of the tenth abdominal, and is valuable 

 in homologizing the larval and pupal segments. 



