192 
ANATOMY AND PHYSIOLOGY 
plified by the Dragon-flies, which have them so pro- 
minent that they are sometimes supposed to be stings. 
By means of them the male is enabled to retain the 
female, and even fly about with her in such a 
position as to have given rise to the erroneous no- 
tion that the genitalia in these insects are placed in 
the anterior part of the body. In this respect they 
form no exception to the general rule. 
PI. V. fig. 1, represents the generative organs of the female of 
Athalia centif olios , from Mr. Newport’s excellent essay on 
that insect : a, a, the ovarial tubes ; c, c, the uterine cavities; 
d , the separate oviducts; e, the common or ejaculatory 
oviduct ; f the spermathcca ; g 9 the poison gland, h , its 
vessel; 10 and 11, the terminal ganglia lying upon the 
ejaculatory oviduct before the sperm-bladder. 
Fig. 2, generative organs of the female of Ranatra linearis , the 
same letters as in the preceding figure indicating correspond- 
ing parts ; g , supposed swimming bladder, with a part of the 
intestine. 
Fig. 3, male generative organs of Athalia centif olios ; a, a, 
smaller testes, 6, b, the ducts, c, larger testes, d, d, vasa de- 
ferentia, e, vesiculae sem inales, A, ejaculatory duct, i , exterior 
valves. 
Fig. 4, generative apparatus of the male of Hydrous piceus ; 
o, a, testes, A, 6, vasa deferentia, c, c, principal seminal ves- 
sels, e, r 9 e, e, various accessory vessels, /*, ejaculatory duct, 
dilated in the middle, g, copulative armature of the vagina. 
Fig. 5, testicle of Silpha obscura greatly magnified. 
Muscular System. — When we reflect on the 
varied movements of insects, their different modes of 
progression, walking, leaping, swimming, flying, &c. 
and the great degree of strength which they exhibit. 
