THE DEE. 23 



tained, and is distinguisliable behind some of the 

 lenses. 



But, stay ! we must not yet part company with the 

 corneal lens of the Bee's eyelet ; for, on closer inves- 

 tigatiouj we shall perceive that it is not a simple, but 

 a compound lens, — a fact of considerable importance, 

 that has, we believe, been overlooked by physiologists. 

 It is composed of two plano-convex lenses (PL IV. 

 fig. 1, 11, Z2) (that is, as you doubtless know, lenses 

 having a plane and a convex surface) of different den- 

 sities or refracting powers, and the plane surfaces of 

 these lenses being adherent, it foUows that the pris- 

 matic corneal lens is a compound double convex lens*. 



The effect of this arrangement is, that if there 

 should be any aberration or divergence of the rays of 

 light diiring their passage through one portion of the 

 lens, it is rectified in its transit through the other. 

 Now it is nothing new to find in the eye of an animal 

 lenses of different densities, but we do not recoUect 

 ever having heard of any other instance where one 

 compound lens has been found consisting of two ad- 

 herent ones of this description f. How remarkable, 

 then, that we should discover such a phenomenon in 

 so humble an animal as the Bee ! Aye, reader ; and 

 how remarkable, too, that we should find such a con- 

 trivance adopted by man in the construction of what he 

 at present considers the most perfect microscopic lens ! 



* We believe the credit of this discovery is due to Dr. J. B. 

 Hicks. 



t It is not unlikely that the eyes of other insects are simi- 

 larly constructed. 



