APPENDIX. 
149 
of seeing very plainly) and proceeded to search for another con- 
venient place for her purpose. The caterpillar has twenty feet 
(six of its legs being of considerable length, the other fourteen 
very short), and in its first stage is of a jetty black, smooth, as 
to privation of hair, but covered with innumerable wrinkles. 
Having acquired its full size, it fixes its hinder parts firmly to 
the leaf of a turnip, or any other substance, and breaking its 
outer coat or slough near the head, crawls out, leaving the skin 
fixed to the leaf, &c. The under coat, which it now appears in, 
is of a bluish or lead- colour, and the caterpillar is evidently di- 
minished in its size. In every respect it is the same animal as 
before, and continues to feed on the turnips for some days lon- 
ger : it then entirely leaves off eating, and becomes covered 
with a dewy moisture, which seems to exude from it in great 
abundance, and appearing to be of a glutinous nature, retains 
any loose or pliant substance which happens to come in contact 
with it, and by this means alone seems to form its chrysalis 
coat. One I find laid up in the fold of a withered turnip-leaf 
(that which I have the honour of enclosing you) was, among six 
others, formed by putting common garden mould to them while 
they were in the exudatory state above described. 
From the generic characters of the fly I conclude it to be a 
Tenthredo of Hill ; but whether that voluminous author be suf- 
ficiently accurate, or whether, from being an almost entire 
stranger to Natural History, I may or may not sufficiently un- 
derstand my book, I must beg leave to submit to your superior 
knowledge of the subject. 
