Mr. Westvrood on a peculiarity of the Ear-ivig. 455 



ment or loss of certain segments of the j^nnulosa in the larva and perfect 

 states, and one which from the great abundance of the insect in [question 

 may, by a carefal examination of its structure in the different periods 

 of its life, be advantageously employed in settling the doubts at present 

 existing upon the subject. The abdomen in many instances is composed 

 of one more joint in the male than in the female insects, (as in the 

 normal Hijmenoptera, &.C.) where the former have seven, and the latter six 

 segments ; but in Dytiscus the reverse takes place, the female having 

 eight, and the male only seven. In the Ear-wig however there is this 

 peculiarity, viz. that in the perfect state of one sex (the male,) the 

 abdomen is developed to the greatest possible extent, as to the number 

 of its segments, and that two of these segments are lost in the opposite 

 or female sex : the terminal segment in both being moreover perfectly 

 alike, leading to the supposition that the lost segments are basal and not 

 apical ones as has been generally supposed, such obsolete apical segments 

 having been considered as employed in the construction of the ovipositor, 



I am. Sir, 



Your very obedient Servant, 



J. 0. Westwood. 

 The Grove, Hammersmith, 

 October 22nd, 1833. 



