IXSECTS : STINGS AND OVIPOSITORS. 137 



" Beside the muscles necessary for the movement of 

 the files, the handle of each is terminated by a curve of 

 the same hard horny substance as itself; which not only 

 furnishes the muscles with a sort of lever, but serves to 

 press, as with a spring, the two files close to the central 

 piece. * 



The use of these instruments is the same as I have 

 already alluded to in the case of the saw-flies. The 

 female Tree-hopper deposits her eggs in holes, which she 

 bores in dead twigs by means of these files and lancets. 

 The branches chosen are said to be easily known by 

 being studded with little oblong elevations, caused by 

 the partial raising of a splinter of wood at the orifice of 

 the hole, to which it serves as a cover. These are 

 arranged in a single line ; the holes which they protect 

 being only half-an-inch in length, and reaching to the 

 pith, whose course they then follow. Not more than six 

 or eight eggs are laid in each hole ; but an idea of the 

 labours of the industrious and provident mother will be 

 formed from the fact that she lays six or seven hundred 

 eggs in the course of the summer. 



* "Insect Architecture," 149. 



