vi INSTINCT 93 



ants, wasps and bees are capable of modifying their whole 

 method of nest-building in well directed adjustment to 

 novel circumstances. 



" Pelopoeus, instead of building in hollow trees or under shelv- 

 ing rocks, as was the ancient custom of the race, now nests in 

 chimneys, or under the eaves of buildings. We have found 

 T. rubrodnctum taking advantage of the face of a straw stack that 

 had been cut off smoothly as the cattle were fed through the 

 winter. The same power of adaptation is shown by Fabre's 

 experiment with Osmia, in which he took two dozen nests in 

 shells from a quarry, where the bees had been nesting for 

 centuries, and placed them in his study along with some empty 

 shells and some hollow stems. When the bees came out, in the 

 spring, nearly all of them selected the stalks to build in as being 

 better suited to their use than the shells." l 



8. By extending the field it would be easy to multiply 

 indefinitely instances of what we may call provisionally the 

 play of intelligence within instinct. I have taken the 

 solitary wasps because their case is typical. There is no 

 doubt of the instinctive character of their plan of action. 

 They can have no " education " from parents, and prac- 

 tically none from one another. Moreover, in many 

 instances their action, otherwise so intelligent, becomes 

 strangely blind. Indeed, some of the strongest instances 

 of " mechanical " instinct may be drawn from this very 

 field. It is among the Hymenoptera, and especially among 

 bees and wasps, that we find instincts most wonderfully 

 plastic in their adaptability on one side, and most strangely 

 stupid in mechanical persistence on another. Some such 

 examples have already been quoted. 2 Many may be added 

 from Mr.andMrs.Peckham'swork. Both among thewood- 

 boxing and mud-dauber wasps they find frequent cases of 



point of going to the obstruction and actually freeing the thread. In this 

 instance the yarn was released, but in others it held fast and there 

 remained when the nest was completed" (J.A.B . p. 348). With this he 

 compares the behaviour of birds endeavouring to carry into their nest- 

 boxes straws or twigs which were too long behaviour like that of a dog 

 trying to carry a stick through a fence, the object being shoved back- 

 wards and forwards in the mouth until held in a certain position when it 

 can be pushed through. In the case of a pair of house wrens the male 

 was an adept in slipping the bill to one end of the twigs and the mate 

 soon acquired the habit from him (p. 371). 1 P. 235. 



2 Those of the Chalicodoma grub, pp. 55, 56, and the Bembex, p. 56. 



