154: EVENINGS AT THE MICEOSOOPE. 



texture is of a clear pale amber, but tlie structure is 

 strengthened by a band which runs along each edge, 

 and by transverse bands crossing at regular intervals, 

 of a denser tissue ; and these are of a rich golden trans- 

 lucent brown. 



From the construction of this implement I should 

 infer that its force is exerted in pulling and not in push- 

 ing ; the direction of the teeth and of the cutting plates 



INNER BAW OF SAW-FLY. 



shows this. The sharp horny point is probably thrust 

 a little way into the solid wood or bark, and then a 

 backward pull brings the teeth and cutting plates to 

 act upon the material, and so successively. And prob- 

 ably these points are the first parts of the whole ap- 

 paratus that come into operation ; the blunter saw of 

 the sheath serving mainly to widen and deepen the 

 course, after the finer points have pioneered the way. 



Tou may like to hear what K^aumur has to say 

 about the manner in which the fly works, especially as 

 I have nothing of my own on the subject, which yet is 

 a most interesting one : — 



" When a female Saw-fly has selected the branch of 

 a rose-tree, or any other, in which to deposit her eggs, 

 she may be seen bending the end of her belly inwards, 

 in form of a crescent, and protruding her saw, at the 



