INSECTS: STINGS AND OVIPOSITORS 159 



deepen the course, after the finer points have pioneered 

 the way. 



You may like to hear what Eeaumur 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 inward, in form 

 of a crescent, and protruding her saw, at the same time, to 

 penetrate the bark or wood. She maintains this recurved 

 position so long as she works in deepening the groove ; but 



INNKR SAW OF SAW-FLY. 



when she has attained the depth required, she unbends her 

 body into a straight line, and in this position works upon 

 the place lengthwise, by applying the saw more horizon- 

 tally. When she has rendered the groove as large as she 

 wishes, the motion of the tendon ceases, and an egg is 

 placed in the cavity. The saw is then withdrawn into the 

 sheath, for about two-thirds of its length, and, at the same 

 moment, a sort of frothy liquid, similar to a lather made 

 with soap, is dropped over the egg, either for the purpose 

 of gluing it in its place, or sheathing it from the action of 

 the juices of the tree. She proceeds in the same manner 

 in sawing out a second groove, and so on in succession, till 

 she has deposited all her eggs, sometimes to the number of 



