154 
ANIMAL INTELLIGENCE. 
make for the open air. He then showed her the way out 
of the open end of the jar, and after having thus learnt 
it, she was able to find the way out herself. This seems 
to show that the bee, like the w T asp on the closed window- 
pane, was able to appreciate and to remember the differ- 
ence between the quality of glass as resisting and air as 
permeable, although to her sense of vision the difference 
must have been very slight. In other words, the bee 
must have remembered that by first flying away from the 
window, round the edge of the jar, and then towards the 
window, she could surmount the transparent obstacle; 
and this implies a somewhat different act of memory from 
that of associating a particular object — such as honey— 
with a particular locality. It is noteworthy that a fly under 
similar circumstances did not require to be taught to find 
its way out of the jar, but spontaneously found its own 
w T ay out. This, however, may be explained by the fact 
that flies do not always direct their flight towards windows, 
and therefore the escape of this one was probably not due 
to any act of intelligence. 
While upon the subject of memory in the Hymenoptera, 
it is indispensable that we should again refer to the ob - 
servation of Messrs. Belt and Bates already alluded to on 
pages 150-51. For it is from that observation rendered 
evident that these sand-wasps took definite pains, as it 
were, to teach themselves the localities to which they 
desired to return. Mr. Bates further observed that after 
thus taking a careful mental note of the place, they would 
return to it without a moment’s hesitation after an absence 
of an hour. The observation of Mr. Belt, already quoted 
in extenso , proves that these mental notes may be taken 
with the utmost minuteness, so that even in the most 
intricate places the insect, on its return, is perfectly con- 
fident that it has not male a mistake. 
With regard to the duration of memory, Stickney 
relates a case in which some bees took possession of a 
hollow place beneath a roof, and having been then re- 
moved into a hive, continued for several years to return 
and occupy the same hole with their successive swarms. 1 
See Kirby and Spence, vol. ii. p. 591. 
