70 INTRODUCTION. 



the foot, is dilated, these claws are turned outwards, 

 and their small curved points find inequalities to 

 which they can adhere even on a surface which mighi 

 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 pui-pose to give 

 an account. (Plate II. fig. 2, Represents the pro- 

 eg of the caterpillar of a butterfly, from Reaumur. 

 Fig. 3, A pair of pro-legs, shewing the manner in 

 which they cling to a branch). 



The head of catei-pillars 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 Highflier, these lobes are produced be- 

 hind into two rather long occipital horns. (Plate III. 

 fig. 6). The conformation of the mouth of lepidop- 

 terous larvae in general, bears considerable resem- 

 blance 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 caterpillar.) It con- 

 sists of an upper lip, with a deep notch in the centre 

 (b) ; two strong mandibles divided at the tip into 

 numerous sharp teeth, which cut the leaves that 

 serve as food (c, c) ; two small and indistinct organs 

 of a soft consistence, lying under the mandibles, 

 which may be regarded as the maxillae ; and an un- 

 der lip {d). Near the summit of the latter, which 

 is usually of a pyrani dal shape, is placed, according 

 to Reaumur, a small conical protuberance, perforated 



