VISION IN INSECTS. 



131 



bees to tlirow 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 Uoriiea) 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 



B c 



A, Eyes of the bee greatly magnified. «, an eye in its perfect slats 

 covered with the cornea; 6, an eye from which the cornea and some of the 

 hexagonal facettes have been removed to show its structure ; c, the three 

 stemmata or coronet eyes ; d, the ganglion of nerves. B, a portion of the 

 surface of the eye deprived of its cornea. O, ditto covered with the cor- 

 nea, and showing the hairs which cover its surface : c, the three small 

 eyes, shown also in page 127. 



* Swammerdam, i, 211. 



■t Ibid, i, 212. 



