THE INSECTS OF THE GREEN LANES. 



199 



strengthened by a back similar to that of the 

 carpenter's well-known "tenon" saw the saws 

 working in a groove at the back. The illustration 

 (Fig. 145), shows the appearance of these ingenious 

 instruments when seen under a microscope. There 



Fig. 144. 



Larva sad as tun: Male Turnip Saw Fly. 

 to 2 diameters. 



The latter enlarged 



are several species of saw-flies, the largest of which 

 is that known as the Great Saw Fly ( Urocerus gigas), 

 which is a very tine insect. It may be seen on 

 some tree trunk, with its body hunched up, trying 

 for a place where it can deposit its eggs. The body 

 is then so bent that the point of the sheath and the 

 ovipositor can make the first impression at the 



