236 ANIMAL INTELLIGENCE. 



in the same vay, and is often not discouraged by five or six 

 miscarriages, but continues its struggle so long that it at 

 length gets over the verge of the place. When it has done this, 

 it does not leave it there, lest it should roll in again ; but is 

 always at the pains of pushing it further on, till it has removed 

 it to a necessary distance from the edge of the pit. 1 



Passing on now to the intelligence of caterpillars, 

 Mr. Gr. B. Buckton, F.R.S., writing from Haslemere, 

 says : 



Many caterpillars of Pieris rapce have, during this autumn, 

 fed below my windows. On searching for suitable positions for 

 passing into chrysalides, some eight or ten individuals, in their 

 direct march upwards, encountered the plate-glass panes of my 

 windows ; on these they appeared to be unable to stand. Ac- 

 cordingly in every case they made silken ladders, some of them 

 five feet long, each ladder being formed of a single continuous 

 thread, woven in elegant loops from side to side. . . . The 

 reasoning, however, seems to be but narrow, for one ladder was 

 constructed parallel to the window-frame for nearly three feet, 

 on which secure footing could be had by simply diverting the 

 track two inches. 2 



In this case it appears clear that we have to do with 

 instinct, and not with reason. No doubt it is the congenital 

 habit of these caterpillars to overcome impediments in 

 this way ; but the instinct is one of sufficient interest to 

 be here stated. 



The following is quoted from Kirby and Spence : 



A caterpillar described by Bonnet, which, from being confined 

 in a box, was unable to obtain a supply of the bark with which 

 its ordinary instinct directs it to make its cocoon, substituted 

 pieces of paper that were given to it, tied them together with 

 silk, and constructed a very passable cocoon with them. In 

 another instance the same naturalist having opened several 

 cocoons of a moth (Noctura verbasci), which are composed of 

 a mixture of grains of earth and silk, just after being finished, 

 the larvae did not repair the injury in the same manner. Some 

 employed both earth and silk ; others contented themselves with 

 spinning a silken veil before the opening. 3 



The same authorities state, as result of their own 

 observation, that the 



1 Animal Biography, vol. iii., pp. 244-5. 

 2 Nature, vii., p. 49. 3 Intr. to Ent., ii., p. 475. 



