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 th 

 female, and even fly about with her in such 

 position as to have given rise to the erroneous no 

 tion that the genitalia in these insects are placed i 

 the anterior part of the body. In this respect the 

 form no exception to the general rule. 



PL V. fig. 1, represents the generative organs of the female ( 

 Atkalia centif olios, from Mr. Newport's excellent essay o 

 that insect : a, a, the ovarial tubes ; c, c, the uterine cavities 

 c/, the separate oviducts; c, the common or ejaculator 

 oviduct ; /, the spermatheca ; g, the poison gland, h, i 

 vessel; 10 and 11, the terminal ganglia lying upon th 

 ejaculatory oviduct before the sperm-bladder. 



Fig. 2, generative organs of the female of Ranatra linearis, th 

 same letters as in the preceding figure indicating correspom 

 ing parts ; g, supposed swimming bladder, with a part of th 

 intestine. 



Fig. 3, male generative organs of Atkalia centifolicB ; a, 

 smaller testes, 6, 6, the ducts, c, larger testes, rf, rf, vasa de 

 ferentia, e, vesiculae seminales, A, ejaculatory duct, i, exterio 

 valves. 



Fig. 4, generative apparatus of the male of Hydrous piceus 

 a, a, testes, 6, 6, vasa deferentia, c, c, principal seminal ves- 

 sels, e, r, e, e, various accessory vessels, /", ejaculatory due 

 dilated in the middle, #, 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 ^orr^e of strength which they exhibit, 



