152 
ANIMAL INTELLIGENCE. 
required three repeated lessons from Sir John before she 
learnt that the window on the other side of the room, and 
away from the direction of her nest, afforded no obstacle 
to her exit. Having learnt this, the fourth time she 
came she again flew to the closed window as before, and 
then, as if but dimly remembering that there was another 
opening somewhere that offered no such mysterious 
resistance to her passage, 6 she took two or three turns 
round the room, and then flew out through the open 
window. 5 Having now taken the bearings of all the room 
upon her own wings, and having again found the difference 
between the two windows in respect of resistance, although 
in all other respects so much alike, the next time she 
came she made in the first instance as it were an experi- 
mental flight towards the closed window, but clearly had 
the alternative of going to the open one in her memory ; 
for on finding the window closed as before, she did not 
alight, but flew straight from the closed to the open window. 
The same thing happened once again, but now, with 
the distinction between the two windows thus fully learnt, 
ard wifh it the perception that in this case ‘the short- 
est cut was the longest way round,’ she never again flew to 
the closed window ; in the forty successive visits which she 
paid through the remainder of that day, and the hundred 
visits or so which she made during the two following days, 
she seems to have uniformly flown to the open window. 
As evidence of forgetfulness , it will be enough to refer 
to the case of another wasp wdiieh, under precisely similar 
circumstances to those just detailed, learnt her way out of 
the open window one day, having made fifty passages 
through it in five hours. Yet Sir John remarks, — 
It struck me as curious that on the following day this wasp 
seemed by no means so sure of her way, but over and over 
a ptin went to the closed window. 
It is further of interest to note, as showing the simi- 
larity of the memory displayed by these insects with that 
of the higher animals, that there are considerable indi- 
vidual differences to be found in the degree of its 
manifestation. 
