668 THE GENERATIVE ORGANS. 



the ovum which is situated at the posterior end of the egg-tube, 

 or that nearest the convex surface of the ovary and the oviduct ; 

 the others, three or four in number, remain rudimentary, but 

 are probably matured in succession after the mature ova are 

 deposited (see p. 5). The most anterior chamber has been 

 named the terminal chamber ; it is the smallest and most rudi- 

 mentary. The membrana propria of the egg-tube is prolonged 

 beyond the terminal chamber, and forms the terminal thread 

 by which the egg-tube is connected with the peritoneal tissue 

 of the concave surface of the ovary. 



The Relation of the Egg-tubes to the Oviduct The egg-tubes 

 have no direct connection with the oviduct. If the fully- 

 developed ovaries are removed from the insect, the egg-tubes 

 can be easily separated from each other after the rupture of the 

 capsule of the ovary. They then diverge from each other and 

 assume a radial arrangement, only remaining attached to the 

 capsule by the terminal threads. 



The relation of the egg-tubes to the oviduct is such that the 

 ova can only be discharged into it by the dehiscence of the 

 tunica propria of the egg-tube, and I have frequently found the 

 empty remains of the membrana propria of the large egg- 

 chamber attached to the rudimentary ova in the anterior part 

 of the egg-tube after the discharge of the ovum from its 

 interior. 



A large number of tracheal vessels are seen covering the 

 external surface of the ovary ; those on its convex surface are 

 very large, and have a stellate arrangement ; they arise from 

 two or three large trunks, and give off numerous branches 

 which ramify in the septal tissue of the ovary, and also minute 

 branches which pass at once on to the egg-tubes. These small 

 vessels fix the convex blind end of the egg-tube to the convex 

 surface of the ovarian capsule. They are easily ruptured, and 

 it is owing to this that the egg-tubes diverge from each other 

 when the peritoneal capsule is ruptured. 



The Structure of the Ovaries in various Insects. The ovaries 

 of many Coleoptera, perhaps of all, and certainly those of 

 Meloe, which I have carefully examined, of many Hymeno- 



