INTRODUCTION. XX111 



even on a surface which might appear to the naked eye almost 

 smooth. Several modifications of this curious prehensile foot 

 occur among the larvae of various kinds of Moths, but of these 

 it forms no part of our present purpose to give an account 

 (Plate II., fig. 2, represents the pro-leg of the caterpillar of a 

 Butterfly, after Reaumur ; fig. 3, a pair of pro-legs, showing the 

 manner in which they cling to a branch). 



"The head of caterpillars is of a harder consistence than the 

 rest of the body, and in most cases seems to be composed of 

 two oval lobes united. In that of the Purple Highflyer these 

 lobes are produced behind into two long occipital horns (Plate 

 III., fig. 6). The conformation of the mouth of Lepidopterons 

 larvae in general bears considerable resemblance to that of 

 several masticating insects in their perfect state (see Plate II., 

 fig. 4, which represents the under side of the head of a cater 

 pillar). It consists of an upper lip, with a deep notch in the 

 centre () ; two strong mandibles, divided at the tip into 

 numerous sharp teeth, which cut the leaves which serve as 

 food (c, c] ; two small and indistinct organs of a soft consistence 

 lying under the mandibles, which may be regarded as the max- 

 illae ; and an under lip (d} . Near the summit of the latter, 

 which is usually of a pyramidal shape, is placed, according to 

 Reaumur, a small conical protuberance, perforated by a smal) 

 hole, through which issues the silken thread which serves so 

 many important purposes in the remarkable changes these 

 creatures undergo. This organ has been named the spinneret. 

 On each side of the under lip, and connected with it at the 

 base, are two minute palpiform bodies (e, e) which may be re- 

 garded as the labial palpi. 



"The efficiency of the organs just described is well evinced 

 by the address and rapidity with which these creatures con- 

 sume the leaves which they select for their food. They in- 

 variably begin to gnaw the margin of the leaf, placing the body 



