THE BUTTERFLY. 55 



altered the relation of the different parts of the 

 head ; in the caterpillar the antennae lay directly 

 beneath the crescent of ocelli ; in the butterfly, 

 on the contrary, they are situated directly above 

 the eyes ; the expansion of the ocellar field has 

 been at the expense of the parts above it, and in 

 this contraction the antennae have passed upward 

 in front of the growing ocellar field until they are 

 found quite above it. In the perfect stage of 

 many of the lower lepidopterous insects, and in 

 a single one of our butterflies, a pair of ocelli are 

 found directly behind the antennae, and are, ap- 

 parently, the hindmost of the larval ocelli, which, 

 it will be recollected, form no part of the little cres- 

 cent in which the others fall, and do not modify 

 the form of the pupal ocellar riband ; these ocelli 

 have passed around the growing ocellar field on 

 the opposite side, to find themselves at last nearer 

 than before to the antennae, which have travelled 

 by the opposite road. 



The antennae themselves have undergone as 

 profound a change in their structure as in their 

 position ; in the larva they closely resemble the 

 maxillae, being made up of a very few joints 

 steadily decreasing in size, the penultimate bearing 

 a long and simple bristle. In the perfect butter- 

 fly they are composed of a great number of joints 

 which may be grouped into three parts the base, 

 the stalk, and the club ; the first two joints form 



