ENTOMOLOGICAL SOCIETY OF FRANCE. 139 



reduced, for its maximum limit of action, to the weight of its 

 own body, a power entirely insufficient in all insects armed 

 with either stings or pointed ovipositors. This consideration 

 alone is sufficient, independently of all anatomical researches, 

 to make us acknowledge the necessity of solutions entirely 

 different from those which are now received. 



3dly, That, moreover, the longitudinal movement of the files 

 is impossible; indeed, had not Reaumur neglected internal 

 anatomy, he m.ust have observed that the two lateral pieces to 

 which he assigns the principal part in the act of perforation, 

 are, in reality, fixed by one of their edges to the penultimate 

 segment of the abdomen, and that the only piece of the three 

 which is really moveable is the central one, which is attached 

 to the extremity of a powerful lever, moved by two large 

 powerful masses of muscle. 



In consequence of this fact, and others which would occupy 

 too much space here, M. Doyere is led to the following con- 

 clusions: — 



1st, That the only movement which the lateral pieces can 

 perform is a rotatory movement, the object of which is to force 

 tlie central piece from the groove in which it lays embedded 

 when at rest. 



2dly, That the lateral pieces, erroneously termed files, only 

 act in the process of perforation as grapnels ; spreading by the 

 action of the central piece, they fix themselves firmly in the 

 wood by their teeth, at their extremity, and thus form the point 

 of resistance wanted in Reaumur's theory. 



Finally, that the middle piece is in reality the instrument 

 used for perforation, and acts at the same time as a means of 

 spreading the grapnels, and fixing their teeth in the fibres of 

 the wood ; and as a punch or perforator, after it has passed the 

 extremity of the grapnels, for perforating deeply into the sub- 

 stance of the wood itself. 



M. Doyere said, that in this theory the entire mechanism, 

 power, and fulcrum, are contained in the penultimate segment 

 of the abdomen, which is consequently sufficient for its func- 

 tions, independently of the other parts of the body. He 

 deferred, till another opportunity, laying before the Society 

 a variety of observations which he had made on the stings of 

 Hymenoptera, the rostrum of Hemiptera, and the ovipositor of 

 many female Orthoptera. 



