Natural History 513 



thrusts the loose earth with great force into the walls, and 

 beats them smooth. Eventually it fixes itself near the top 

 of the shaft so that the roof of its head forms a trap-door. 

 When an ant or some other small insect settles down on 

 this living lid, the grub suddenly explodes like a jack-in-the- 

 box, hurling its victim violently against the hard upper 

 edge of the shaft-wall. The sucked body is afterwards 

 jerked out. The world is full of these inventions. 



How are we to understand the behaviour of one of the 

 Digger Wasps which lays its eggs in a sunk shaft, and 

 provisions this with paralysed caterpillars? While the 

 hunting and storing are in progress, the wasp shuts the 

 mouth of the shaft after each visit, but does so in a rough- 

 and-ready fashion. When the larder is full, however, it seals 

 the entrance with earth and makes a neat job of it; nay, it 

 takes a minute pebble in its jaws and beats the earth smooth. 

 Who said animals could not use tools? It seems that using 

 the pebble is not part of the instinctive routine, but is an 

 individual touch, probably with more vivid awareness than 

 is associated with the rest of the agency. But the difficulty 

 is to think of the origin of either the routine or the finishing 

 touch without postulating intelligence, or, at least, some 

 appreciation of significance. 1 



Homing 



It is well known that ants and bees can find their way home 

 from a distance. Ants evidently take impressions, by touch, 

 sight, or sense of smell, of certain signposts. There may even 

 be a "muscular memory" of the movements effected and of the 

 amount of work done. Probably ants improve gradually in their 

 way-finding as they learn to make use of a combination of the 

 various hints. An interesting experiment suggested that bees 

 build up a knowledge of the country round about the hive. 

 Professor Yung of Geneva took twenty bees from a hive near 

 the lake and liberated them at a distance of six kilometres in the 

 country. Seventeen returned to the hive, some within an hour. 



1 J. Arthur Thomson, Secrete of Animal Life 



