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 lip, and they are simple eyes or ocelli. 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. 
HEAD OF A HORNET ( Vespa cralro). 
Enlarged view, showing the lateral compound eyes, the ocelli in front on the forehead, 
and the antennae. 
The antennae 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 antennae 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 
