122 INTELLIGENT BEHAVIOUR 
away from home, but as they occupy the same nest all summer 
they, of course, grow more and more familiar with their sur- 
roundings, until they become so thoroughly acquainted with 
them that they can find their way without the least difficulty. 
We have no doubt that with them, as with the solitary wasps, 
the faculty is not instinctive, but is the direct outcome of 
individual experience.” 
In the interesting pages of the works in which Dr. and Mis. 
Peckham describe their investigations, there are many observa- 
tions which show that wasps are capable of intelligently profiting 
by the experience which their instinctive behaviour places them 
ina position toacquire. The inherited tendencies and aptitudes 
pave the way for acquired modification and accommodation of 
behaviour. ‘lo catch and paralyze spiders, to dig and prepare 
a tunnelled nest, and to carry the prey to the nest, all this 
affords the instinctive basis; but when the observers tell us 
that they ‘“‘ have several times seen wasps enlarge their holes 
when a trial had demonstrated that a spider would not go in,” 
and even on one occasion without trial when an unusually 
bulky spider was brought, there is something beyond instinct ; 
there is intelligent adjustment to special circumstances given 
in experience. Presumably intelligent is the habit frequently 
observed in one species of Pompilus, and occasionally in another, 
of hanging the paralyzed spider in a crotch of a branching 
stem, usually of bean or sorrel, where it will be safe from the 
depredation of ants. On one occasion Dr. Peckham, desirous 
of seeing the exact manner in which the victim was stung, 
substituted an unhurt spider for that which the wasp had 
paralyzed.* ‘¢ According to the habit of its species when 
danger threatens, it kept perfectly quiet, and when the wasp 
returned it was hanging there as motionless as a piece of dead 
matter ; but she would not touch it ; she hunted all over that 
plant and then over several others near to it, returning con- 
tinually to look again at the right spot. After five minutes 
she flew off in the direction of the woods to catch another 
spider. Why did she go to the woods? Why did she not 
* Up. cit.. pp. 131, 132. 
