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 might 
appear to the naked eye almost smooth. Several 
modifications of this curious prehensile foot occur 
among the larva? of various kinds of moths ; bnt 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, from Reaumur. 
Fig. 3, A pair of pro-legs, shewing 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 he 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 larva? 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 maxillte ; and an un- 
der lip (d). Near the summit of the latter, which 
is usually of a pyramidal shape, is olacod, according 
to Reaumur, a small conical protuberance, perforated 
