PERCEPTION OF COLOUR. 321 . 



I then removed the yellow paper and honey, and 

 placed the honey which had been on the green paper 

 about a foot from it on the table. 



At 8.15 she returned and lit on the green paper, 

 but immediately flew off to the honey. I then trans- 

 posed the honey and the paper. 



At 8.24 she returned and again lit on the paper, but 

 immediately flew off to the honey. 



Thus, therefore, though it is clear that wasps can 

 distinguish colours, they appear, as might be expected 

 from other considerations, to be less guided by them 

 than is the case with bees. 



I have been much struck by the industry of wasps. 

 They commence work early in the morning, and do not 

 leave off till dusk. I have several times watched a 

 wasp the whole day, and from morning to evening, if 

 not disturbed, they worked without any interval for rest 

 or refreshment. One of my wasps made no less than 

 94 journeys from the nest to the honey in one day. 

 The details of some of these observations are given in 

 the Appendix, p. 405. 



Every one has heard of a ' bee-line.' It would be 

 no less correct to talk of a wasp-line. On August 6 

 I marked a wasp, the nest of which was round the 

 corner of the house, so that her direct way home 

 was not out of the window by which she entered, 

 but in the opposite direction, across the i*oom to a 

 window which was closed. I watched her for some 

 hours, during which time she constantly went to the 



