VISION IN INSECTS. 



131 



bees to throw it off, or brush it away the more easily, 

 by a friction which bees perform with their feathered 

 legs. Similar hairs are found in the facetted eyes of 

 many other insects*. 



Behind the outer coat (cornea) of the bee's eye, 

 there is an opaque substance, like what is called the 

 paint (uvea) in the eyes of quadrupeds and man. In 

 bees this is of a deep purple colour ; in other insects 

 it is green; in some blue; in some black; and, in 

 others, it has a very beautiful mixture of various 

 colours f. 



shown also in page 1 27. 



* Swammerdam, i. 211. 



