SENSES OF BEES. 313 



Transcends in organs apt this puny fly, 



Her fine-strung feelers, and her glanceful eye, 



Set with ten thousand lenses." EVANS. 



The eyes of all insects are immoveable, and 

 have neither iris nor pupil nor eyelids to cover 

 them : but this apparent defect is amply made up 

 to them in a variety of ways : in the case before 

 us, by the complex structure of the organs. 

 REAUMUR performed an experiment similar to that 

 which I have just related of LEEWENHOECK, and 

 with a like result. HOOKE computed the lenses 

 in the eye of a horse-fly to amount to nearly 7000. 

 LEEWENHOECK found more than 12,000 in that 

 of a dragon-fly ; and 17,325 have been counted in 

 the eye of a butterfly. The lenses are most 

 numerous in the beetle, and so small as not to be 

 easily discoverable under a pocket microscope, 

 except the eye be turned white by long keeping. 



The peculiar construction of the bee's eye, for 

 seeing objects best at a moderate distance, will 

 account for the circumstance noticed by WILDMAN, 

 and also for the following observation of DR. 

 EVANS. " We frequently observe bees flying 

 straight homewards through the trackless air, as 

 if in full view of the hive, then running their heads 

 against it, and seeming to feel their way to the 

 door with their antennae, as if totally blind." SIR 

 C. S. MACKENZIE remarked the imperfect vision 

 of bees, and how very much puzzled they are to 

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