INSECTS I STINGS AND OVIPOSITORS. 137 



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 in- 

 dustrious 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. 



