24 



TRANSFORMATIONS OF INSECTS. 



are situated on either side of the head ; these are the compound 

 or facetted eyes. The others are found upon the head, above the 

 upper hp, and they are simple eyes or oceUi. The compound eyes 

 are never found in the larva, and yet it is evident that the simple 

 organ of the caterpillar is developed into the wonderful eye of the 

 butterfly, with its ten or fifteen thousand hexagonal lenses. The 

 compound eyes are generally largest in the male insects, and they 

 are frequently magnificently decorated with hairs and with metallic 

 colours. The ocelli are often placed between the compound, and 

 glance like diamonds. 



Av;«li1i'i 



;j\^\\ iiiv^\\\^\VJl|ilii) '/fid//'/'/ 



HF.AD OF A HORNET ( Vespa crabro). 



Enlargf^. vic.v, siiowing the lateral compound eyes, the ocelli in front on the forehead, 



and the antennae. 



The antenna; present every imaginable shape and length, and 

 are situated on different parts of the head in different insects. 

 They are always very small in the larva ; they have, however, 

 important functions in the perfect insect, and in which they 

 attain their greatest development. 



One of the results of the progressive development of the insect 

 is the addition of the organ of hearing to that of touch, which last 

 probably exists in the small antennae of the larvae. Erichson, a 

 German entomologist, and Dr. Braxton Hicks, F.R.S., discovered 

 numerous depressions in the antenna of fully developed insects, 

 which are lined with a delicate membrane ; and the last-named 

 naturalist found that a small cell, made up of several others, and 



