Mr. Westwood on a peculiurity of the Ear-wig. 455 
ment or loss of certain segments of the 4nnulosa in the larva and perfect 
states, and one which from the great abundance of the insect in ‘question 
may, by a careful 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 Hymenoptera, &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 onesas 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. O. WEsTWoop. 
The Grove, Hammersmith. 
October 22nd, 1833, 
