OPERATIVE TOOLS. 327 



have just been viewing, together with insect weapons of attack 

 and self-defence. Wonderful alike for its simplicity and the 

 manifold uses which it is made to serve, here is the double 

 pickaxe, each blade toothed on the inner edge, acting thus all 

 the better as a fast-holding pair of forceps, as well as a cutting 

 chisel. This, the compound tool, only slightly varied with 

 different possessors, is the only tool of the "wasp mason, 

 carpenter, and paper-maker." A pair of wasp mandibles or 

 jaws constitutes the instrument now before us.* A hard horny 

 substance is the material of W 7 hich this and nearly all insect 

 tools are constructed. 



A saw is the implement which next presents itself, a tool 

 much resembling, only more complicated than that of our 

 own carpenters : we may call it rather a pair of saws, or a 

 compound saw, w r hen in use working simultaneously at one 

 cut. The instruments are so exceeding fine and delicate as to 

 need support, and we see accordingly that their backs are set 

 within a groove. The teeth, instead of being simple, are 

 denticulated with others cut more finely, which confers on this 

 tool the additional properties of a rasp or file.* 



What are its uses and by whom employed ? Its purpose is 

 to cut grooves in the branches of trees and shrubs for recep- 

 tion and protection of insect eggs ; and the insect by whom 

 the grooves are cut is a maternal saw-fly a very common 

 four-winged fly, usually black and yellow or brown, of which 



* See Vignette. 



