INTERNAL ANATOMY. 95 



the egg does not simply emerge from the vulval 

 opening; it passes through a very long, protrusible, 

 Membranous ovipositor with three lobes at the end to 

 guide it during oviposition, so that the genital suckers 

 could not possibly touch the egg when it is passing 

 from the body and being deposited. 



May it not be possible that these organs have some 

 general tactile function, and serve to some extent as 

 feelers to guide the action of the parts during the 

 various processes connected with reproduction ? ; feelers 

 connected with the genital organs are not unknown in 

 the Arthropoda. 



The Copulative Suckers. These have already been 

 referred to at page 94, and but little more need be 

 said about them; they are present in the males only 

 of the genera Mselia, Histiog aster, Aleurobius, Rhizo- 

 glyphus, Tyrogli/phus, and Ghortocjlyphus ; they are 

 also very common, indeed usual, in the males of the 

 Sarcoptida3. They consist of a single pair of large 

 suckers one on each side of the anal aperture, and 

 almost close to it ; these organs are typical suckers, 

 and are considerably exerted at the time of coition 

 and then only. The organ is protruded by fluid 

 driven into it from the body cavity, and is retracted 

 for sucking action by a muscle inserted into the centre 

 of the inner side of the disc. 



In many species, especially of the genus Tyro- 

 glyphus, the male only has a pair of small sucker-like 

 tubercles on the inner side of each fourth leg. These 

 doubtless assist in holding the female, probably at the 

 first moment of seizure. 



THE FEMALE REPRODUCTIVE ORGANS. PI. B, figs. 8 10 ; 

 PL C, figs. 1, 11. 



These must be considered to have been first correctly 

 described by Grudden in 1861 ; they have since been 

 investigated and described in much greater detail by 

 Nalepa. Several less correct attempts, had been made in 



