236 
ANIMAL INTELLIGENCE. 
Ln the same way, 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. 1 3 Intr. to Ent.> ii. s p, 475. 
