BENNETT: — EARWIGS 53 



back to back'until the forceps touch. Then the male completely inverts the end of his 

 abdomen and, of course with inverted forceps, proceeds to back under the female 

 until the required position is reached. (See Figure 2.) 



The forceps of the male and of the female differ, as we have alreadj- noticed, 

 those of the male being the more rounded and irregular. (The original type seems 

 to have been that of the female, for both sexes have this type until the last stage.) 

 The shape of the male forceps also varies greatly, male differing from male (see 

 Figure i, a and c) in a marked manner, while that of the female is always the 

 same. I wondered at first why the forceps of the male should be curved as they 

 are. I noticed that the right one frequently laps a little over the left when they are 

 closed, and that it is usually a little more bent than the left. When I saw that the 

 male in mating inverts his forceps and that therefore the right is the one to touch 

 the ground, I could readily see at least one advantage in the present shape. The 

 right is the more bent of the two, often with the point at right angles to his body, 

 or sometimes even pointing a little forward. It would, therefore, not offer the 

 obstruction to his backward movement that it would if his forceps were shaped like 

 those of his mate. This applies certainly to the earwigs which I had in confine- 

 ment. Still so great is the difference both in shape and dimensions of other species 

 of earwigs that I dare not state it as a rule applicable to all. 



