23 HUMBLE CREATURES. 



shall compare it to a bundle of telescopes (3500, re- 

 member !), so grouped together that the large ter- 

 minal lenses present an extensive convex surface, 

 whilst, in consequence of the decreasing diameter of 

 the instruments, their narrow ends meet and form a 

 smaller concentric curve. Now, if you can imagine 

 it possible to look through all these telescopes at one 

 glance, obtaining a similar effect to that of the stereo- 

 scope, you win be able to form some conception of 

 what is probably the operation of vision in the Bee. 

 This comparison, however, presents but a crude and 

 imperfect idea of the organ in. question, and we shall 

 now accurately describe one of these "telescopes," 

 as we have popularly termed them. 



Each of the eyelets or " ocelli," which, aggregated, 

 constitute the compound eye of a Bee, is itself a per- 

 fect instrument of vision, consisting of two remark- 

 ably formed lenses, namely an outer " corneal " lens 

 (PL IV. fig. l,aa a), and an inner or " conical" 

 lens (6). The " corneal" lens (a) is a hexahedral or 

 six-sided prism, and it is the assemblage of these 

 prisms that forms what is called the "cornea" of 

 the compound eye. 



This " cornea " may easily be peeled off, and if the 

 whole, or a portion, be placed under the microscope, 

 the grouping of the beautiful lenses becomes di- 

 stinctly visible. In PL IV. fig. 3, which represents a 

 portion of the cornea magnified, a little of the sub- 

 jacent layer of colouring-matter [pigmentum nigrum), 

 of which we shall speak hereafter, has also been re- 



