138 



OVARIES 



number is greater, and in the queen-bee it is increased to about 

 180. In the Queens of the Termitidae, or white ants, the ovaries 

 take on an extraordinary development ; they fill the whole of the 

 greatly distended hind-body. Three thousand egg-tubes, each con- 

 taining many hundred eggs, may be found in a Queen Termite, so 

 that, as has been said by Hagen, 1 an offspring of millions in number 

 is probable. There is considerable variety in the arrangements 

 for the growth of the eggs in the egg-tubes. Speaking concisely, 



the tubes may be considered to be 

 centres of attraction for nutritive 

 material, of which they frequently 

 contain considerable stores. Next 

 to the terminal thread, of which we 

 have already spoken, there is a 

 greater or smaller enlargement of 

 the tube, called the terminal cham- 

 ber ; and there may also be nutri- 

 ment chambers, in addition to the 

 dilatations which form the egg-cham- 

 bers proper. Korschelt 2 distinguishes 

 three principal forms of egg-tubes, viz. 

 (1) there are no special nutriment 

 chambers, a condition shown in Figure 

 74 ; (2) nutriment chambers alter- 

 nate with the egg-chambers, as shown 

 in our Figure of an egg - tube of 

 FIG. 74. Sex organs of female of Dytiscus marginalis ; (3) the ter- 

 Scoiia interrupta (after Dufour) ; m i lia i chamber takes on an unusual 



a, egg - tubes ; o, oviducts ; c, 



poison glands ; d, duct of acces- development, acting as a large nutri- 

 sory gland (or spermatheca) ; e, ment chamber, there being no other 



external terminal parts of body. ' 



special nutriment chambers. This 



condition is found in Rhizotrogus solstitialis. The arrangements 

 as to successive or simultaneous production of the eggs in the 

 tubes seem to differ in different Insects. In some forms, such as 

 the white ants, the process of egg-formation (oogenesis) attains a 

 rapidity that is almost incredible, and is continued, it is said, for 

 periods of many months. There is no point in which Insects 

 differ more than in that of the number of eggs produced by one 



1 Linnaea entomoloyica, xii. 1858, p. 313. 

 " Zeitsclir. wiss. Zool. 1886, xliii. p. 539. 



