140 



development. In the mature ovary the lower 

 follicles have in every tube become the large 

 completely-formed egg (Fig. 39). 



The oviducts are muscular tubes passing from 

 the ovaries. They join beneath the rectum to 

 form the common oviduct, which is still more 

 abundantly supplied with muscle fibres, and which 

 eventually opens beneath the anus. 



The spermatheca is a chitinous sac, which in 

 the impregnated female is filled with a mass of 

 spermatozoa. Its duct is long and twisted and 

 opens into the common oviduct near its termina- 

 tion. (In Ciilex there are three spermathecae.) 



The mucus gland, globular or ovoid in shape, 

 opens by a short duct into the same region. 



The Fat -body. — The adipose tissue is disposed 

 in two ways. 



1. As a general lining to the body wall, 

 being nearly everywhere present directly beneath 

 the cuticle, and 



2. As lobular masses lying in among the 

 organs and muscles. Thus a large pad lies over 

 the compound thoracic ganglion, and sends pro- 

 cesses which lie in among the salivary glands and 

 other viscera. Other smaller masses lie in the 

 head and abdomen. 



Histology 



Methods. — The examination of the fresh tissues 

 frequently reveals structures not easily seen in fixed 

 preparations. The tissues are best dissected out 

 in normal sahne of low tonicity, 0-3 or o'4 per 

 cent., as insect juices have a lower isotonic point 

 than those of mammals. Better preparations of 



