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 wasp 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 

 way 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 made 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. 



