36 WASPS AND THEIR WAYS 



ently in different species, so that by their 

 faces they are known, one method of 

 classification being founded on the facial 

 markings. Wasps quickly distinguish 

 colours. This has been proved by put- 

 ting papers of different colours over the 

 entrance holes to the nests of the ground 

 wasps and watching what happened. Red 

 paper, with a hole for the wasps to go 

 through, was put over a nest and occa- 

 sioned great excitement, but in the course 

 of about three hours the wasps became 

 accustomed to their decorative doorway 

 and went in and out through it as though 

 that had always been their habit. 



When the red paper was exchanged for 

 blue the wasps were as excited as before, 

 though they more quickly became accus- 

 tomed to it. 



When the wasps had become used to 

 going in and out through the blue paper 

 a number of them were caught, the 

 blue paper was removed, and the wasps 



