1884.| Anatomy and Physiology of the Family Nepide. 361 
brata so in the Insecta, two kinds of organs are concerned in this 
process, the mutual action of whose products upon each other, is 
usually necessary for the formation of new individuals. These 
organs are the male organs or testes, producing spermatozoa, and 
the female organs or ovaries, producing eggs. 
I. THe MALE GENERATIVE SYSTEM. 
The testes of the male Belostoma lie in the anterior portion of 
the abdominal cavity, on each side of the pyloric end of the 
stomach. They consist of a rounded body, which in reality is a 
membranous sac, mounted on a sort of receptacle composed of 
five pieces closely packed together. From each of these five 
pieces, arise spermiferous tubes which are much matted in the 
membranous sac. (Fig. 12.) The vas deferens, which leads back- 
ward from the testes, is thread-like for the first half of its course, 
and then enlarges into a tube, which joins with the one from the 
Opposite side to form the ductus ejaculatorius, which conducts the 
spermatic fluid to the organ of intromission. (Fig. 11.) This is 
ormed by two pieces, a pick-shaped structure above and a spoon- 
shaped one below it; both organs are situated on the genito-anal 
Prolongation, which corresponds to a dorsal and ventral part of a 
seventh abdominal segment. The prolongaticn is provided with 
copulatory hooks, which in the femiale are rudimentary. 
In Ranatra, the general arrangement of the generative appa- 
atus is the same, though in detail, somewhat different. The 
“permiferous tubules are confined in an elongated sac, which is 
much farther forward than in Belostoma, and the vas deferens, 
SE enlarging, is coiled several times upon itself before passing 
nto the ductus ejaculatorius (Fig. 10.) The coils are compact 
a: form a lenticular enlargement on the vas deferens, some- 
mes mistaken for the testes, 
Il. Tut FEMALE GENERATIVE SYSTEM. 
The Ovaries of the female consists of two series of five tubes 
Fads one on either side of the body. These terminate in the 
Ti where their small pointed ends are joined together by 
ma threads, which serve also to attach them in the thorax. 
mere ng outward they gradually grow larger until they all 
aay fhe calices, the tubes of which unite to form the vagina or 
ct. These organs vary greatly in size according to the sea- 
So) . ‘ ; z . 
n, Sometimes quite contracted,and sometimes so distended with 
