454 Mr. Westwood on a peculiarity of the Ear-wig. 
Art. LXJ. Ona remarkable sexual peculiarity exhibited by 
the Ear-wig, (Forficula auricularia, Linn.) By J.O. West- 
woop, Esq., F.L.S., &c. 
Sir, 
May I be allowed space for a remark or two in explanation of an 
observation of mine contained in the last Number of this Journal which 
may have had somewhat of the appearance of an act of injustice towards 
the celebrated French entomologist M. Leon Dufour. 
In noticing the erroneous nature of the decapod annulose theory, I 
instanced the Ear-wig as a proof of the hexapod structure of insects, 
that species having the abdomen composed of nine distinct segments, 
adding that M. Dufour had unfortunately represented the abdomen with 
only seven segments, (Ann. Sc. Nat. 13, pl. 19, f. 2 A.) the two basal 
ones being omitted. 
Being anxious a short time since to ascertain the situation of the 
spiracles along the body of an insect in which all the thirteen segments 
were fully developed in the perfect state, (in the hopes of discovering a 
clue to the solution of the remarkable question raised by the French 
entomologists relative to the structure of the Hymenopterous thorax, 
also noticed in my observations contained in the last Number of this 
Journal), I caught some Ear-wigs, in each of which I was not a little 
surprized to find that only seven abdominal segments existed ; fearful that 
I had erred in my previous remarks I immediately re-examined my dis- 
sections in which nine distinct abdominal segments were clearly observ- 
able. On again looking at my live Ear-wigs they all proved to be 
females, whiist my dissected specimens were males. Here then we have 
the remarkable fact unnoticed by Latreille, Dufour, &c. that the male Ear- 
wig has two more abdvuminal segments than the female, and hence the 
correctness both of M. Dufour’s figure, (at least if taken froma female, 
which however by no means appears from his “‘ Explication des planches,’’) 
as well as of my own observations. 
This circumstance is not a little interesting in reference to the develope- 
