THE FEMALE GENERATIVE OBQANS. 109 



is covered by a dense mesh of trachea! vessels. When the 

 insect first emerges from the pupa, the ovaries are not l-30th of 

 an inch in diameter, but when the ova are mature they occupy 

 the greater part of the abdominal cavity ; for the mature ova 

 are l-20th of an inch in length, and on the most moderate com- 

 putation, each ovary contains 300 mature ova, so that a single 

 female is capable of producing at least 2,400 ova, supposing 

 the four sets in the ovary to be matured in succession. 



The ovarian follicles appear to consist of structureless 

 membrane, largely supplied with delicate trachea! vessels, and 

 the oviducts in the young insect consist entirely of an exceed- 

 ingly fine membrane. When mature, they exhibit a thick 

 muscular coat of transverse and longitudinal fibres. They 

 unite with each other at the base of the ovipositor, and are 

 continued to its extremity as a common oviduct. 



About l-20th of an inch from the extremity of the ovipositor, 

 the albumen glands and seminal receptacles open into the 

 common oviduct. 



The albumen glands are simple sacculate glands, l-15th of an 

 inch in length, which open into the oviduct by narrow necks. 

 They secrete a viscid fluid, which covers the ova after impreg- 

 nation, rendering them opaque. It is quite insoluble in water, 

 but is immediately dissolved by aether, rendering the ova 

 again transparent. 



The seminal receptacles (Plate X., fig. 7) are three in 

 number, two upon ihe right and one upon the left side. Each 

 consists of an ovate dark brown chitinous capsule, measuring 

 about 1-1 20th of an inch in its long diameter, connected with 

 the oviduct by an elastic tube, l-20th of an inch in length, 

 continuous with the wall of the capsule. 



