82 EYES OF INSECTS. 



no reason to suppose, inasmuch as we, with our pair of single 

 eyes, are not in the habit of seeing double, and as (according 

 to Muller) " each individual facet of an insect's compound eye 

 can survey but a small space in the field of vision, each only 

 contributes to the perception of all things within it. Each 

 separate one does not at the same time see all such objects, 

 but only conveys its impression to the nervous filament with 

 which it is supplied, and the latter being united in the great 

 optic nerve, a common and distinct image is ultimately 

 produced." 



The compound eye of an insect would not seem, therefore, 

 to multiply objects to its natural possessor, but it has never- 

 theless been converted by the ingenuity of man into a curious 

 optical instrument of multiplying power. Through the eye 

 of a Flea (so placed as to command objects with the assist- 

 ance of a microscope) a single soldier has appeared as at once 

 diminished and multiplied into a Lilliputian army, while the 

 flame of a single candle has been made, in like manner, to 

 represent a grand miniature illumination. 



The eyes of Butterflies present on examination the ap- 

 pearance of a multiplying glass of this description, the facets 

 bearing a resemblance to a cut diamond. The ocelli or simple 

 eyes, appearing as little points of crystal, seated mostly above 

 the compound pair, and usually three in number, are supposed 

 to be intended, generally as well as in Bees, for the purposes 

 of near vision such as examination of leaves, flowers, &c, 

 serving for food, or presenting it in the smaller "fry" by 

 which they are frequented. 



The position of Insect eyes is in several cases worthy of 

 especial notice : affording in their variations from the common 

 type, so many remarkable instances of that kind creative care 

 which adapts each organ with exquisite nicety to its intended 

 use. 



In that little shining Beetle, called the Whirlwig, which 

 may be seen every summer's day whirling about the surface of 



