20 SOCIAL LIFE IN THE INSECT WORLD 



Buried underground at a depth of twelve or fifteen inches, 

 the larva, when ripe for escape, could hardly judge 

 whether the meteorological conditions were favourable. 

 The subterranean climate varies too little, changes too 

 slowly, and would not afford it the precise information 

 required for the most important action of its life — the 

 escape into the sunshine at the time of metamorphosis. 

 Patiently, for weeks, perhaps for months, it digs, clears, 

 and strengthens a vertical shaft, leaving only a layer of 

 earth a finger's breadth in thickness to isolate it from the 

 outer world. At the bottom it prepares a carefully built 

 recess. This is its refuge, its place of waiting, where it 

 reposes in peace if its observations decide it to postpone 

 its final departure. At the least sign of fine weather it 

 climbs to the top of its burrow, sounds the outer world 

 through the thin layer of earth which covers the shaft, 

 and informs itself of the temperature and humidity of the 

 outer air. 



If things are not going well — if there are threats of a 

 flood or the dreaded bise — events of mortal gravity when 

 the delicate insect issues from its cerements — the prudent 

 creature re-descends to the bottom of its burrow for a 

 longer wait. If, on the contrary, the state of the atmo- 

 sphere is favourable, the roof is broken through by a 

 few strokes of its claws, and the larva emerges from its 

 tunnel. 



Everything seems to prove that the burrow of the 

 Cigale is a waiting-room, a meteorological station, in 

 which the larva makes a prolonged stay ; sometimes 

 hoisting itself to the neighbourhood of the surface in 

 order to ascertain the external climate ; sometimes re- 

 tiring to the depths the better to shelter itself. This 



