154 



EVENINGS AT THE MICKOSCOPE. 



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

 strengthened by a band whicb 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 



IXXEK SAW OF SAW-FLT. 



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 aj)- 

 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. 



You may like to hear what Eeaumur has to sav 

 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 : — 



" Wlien 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 th.e 



