WONDERS OF INSTINCT 209 
head is always turned towards the door.” This 
seems a minute detail, but the strength of a chain 
is that of its weakest link. The supple grub can 
turn this way or that in its chamber, but the coming 
Cerambyx will not be able to turn or bend. ‘“ He 
must absolutely find the door in front of him, lest 
he perish in the casket. Should the grub forget this 
little formality, should it lie down to its nymphal 
sleep with its head at the back of the cell, the Cap- 
ricorn is infallibly lost; his cradle becomes a hopeless 
dungeon.” But the grub forgets as little as it 
learns! 
The third feature which Fabre’s studies bring 
into prominence is the limitation of instinct. Often 
subtle and perfect, without a loose thread from 
first to last, the instinctive routine often ends in 
an almost ridiculous fiasco, when a grain of in- 
telligence would have saved the situation. The 
fact is, of course, that the instinctive capacity has 
been slowly and exquisitely adapted for the ninety- 
nine per cent. of normal circumstances, not to meet 
the one per cent. of exceptional contretemps. 
Strange it is, however, that the burying beetles will 
allow themselves to pine away in an artificial prison 
which has for such expert tunnel-makers a widely- 
open door—widely open physically, but closed 
psychically. They often show great pertinacity in 
trying to bury a mouse in difficult conditions, but 
Fabre’s ingenious experiments showed that they 
were baffled by simple tricks of suspension where a 
touch in the right direction would have made the 
