454 Mr. West wood on a peculiarily of the Ear-wig. 



Art. LXI. On a remarhahle ae.vnat pecidiarity exhibited hy 

 the Kar-wig, ( Fo7'J{cida anriai/aria, Linn.) JBy J. O. West- 

 WOOD, Esq., F.L.S., bic 



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, pi. 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 Hyraenopterous 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, whilst 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 abdominal segments than the female, and hence the 

 correctness both of M. Dufour's figure, (at least if taken from a 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- 



