442 Mr. Newport on the Anatomy and 



error has been committed by M. Pictet in regard to the sexes of Pteronarcys, 

 as I shall presently show. 



The male internal organs are very simple in their character. They consist 

 of a pair oi testes (fig. 14 x) with long convoluted ducts, and a pair of short 

 vesiculce seminales (y). These, with the ducts, unite behind the terminal gan- 

 glion of the nervous cord in a short vas deferens on each side, which termi- 

 nates in a long ductus ejaculatorius and organ of intromission (z). 



The testes are placed above and on each side of the alimentary canal in the 

 fifth, sixth and seventh segments of the abdomen. Each testis (x) is formed 

 of a multitude of pear-shaped follicles attached around, and opening into a 

 common canal. These follicles (fig. 15) are filled with rounded bodies, which 

 line their interior, the proper secretory structures for the production of sper- 

 matozoal cells, some of which, of minute size, I have observed at the junction 

 of the follicles with the canal. The aggregation of follicles together forms 

 an elongated oval testis, which terminates in a long convoluted duct. The 

 vesiculce seminales {y) are short, thick ceecal organs of an opake white colour, 

 and folded twice or thrice on themselves. They occupy the posterior part of 

 the eighth abdominal segment, and are continuous backwards with the vasa 

 deferentia on each side, at the point of union of the ducts from the testes. 

 The vasa deferentia thus formed pass backwards to the margin of the eighth 

 abdominal segment, and then unite laterally and pass to some distance for- 

 wards, where they end in a single vessel, a long ductus ejaculatorius, which 

 returns backwards to the outlet of the tenth segment to end in the penis {z). 

 The object of the great length of this duct, and of the arrangement of the 

 organs, seems to be to facilitate the transmission of the male influence at the 

 time of union of the sexes. The long process on the under surface of the 

 eighth segment (fig. 16) appears to be elevated and employed by the male as 

 an organ of prehension, to grasp and retain the terminal segment of the 

 female, the body of the male being reversed during the act, as in the Derma- 

 ptera and Orthoptera. By the elevation of the process of the eighth segment, 

 and the elongation of the ninth and tenth segments, the position of the vesi- 

 culce and ductus ejaculatorius is altered, and the passage of the male influence 

 is then direct and unimpeded. 



M. Pictet, however, has mistaken the process in the male for an ovipositor. 



