the Black Canker Caterpillar, 221 
The caterpillar has twenty feet (fix of its legs being of con- 
fiderable length, the other fourteen very ffiort) and in its firft 
flage is of a jetty black, imooth as to . a privation of hair, but 
covered with innumerable wrinkles. Having acquired its full 
fize, it fixes its hinder parts firmly to the leaf of a turnip, or 
any other fubftance, and .breaking its outer coat.or Hough near 
the head, crawls out, leaving the Ikin fixed to the leaf, &c. 
1 ho under coat, which it now appears in, is of a blueifh or 
lead colour, and the caterpillar is evidently diminifhed in its fize. 
In every refpeclit is the lame animal as before, and continues to 
feed on the turnips for lome days longer : it then entirely leaves 
otf eating, and becomes covered with a dewy moifture, which 
feems to exfude from it in great abundance, and appearing to be 
of a glutinous nature, retains any loofe or pliant fubftance 
which happens to come in contact with it, and by this means 
alone feems to form its chryfalis coat. One I find laid up 
in the fold of a withered turnip leaf (that which I have dis- 
honour of inclofing you) was, among fix others, formed by 
putting common garden mould to them while they were in the 
exfudatory flute above del'cribed. 
From the generic characters of the fly I conclude it to be a 
Tenth redo of hill ; but whether that voluminous author be 
f , v j • f V 
fufficiently accurate ; or whether, from being an almoft entire 
ftranger to natural hiftory, I may, or may not, fufficiently 
underftand my book, 1 muft beg leave to fubmit to your lupe- 
rior knowledge of the lubjeCt. 
I am endeavouring to extend my obfervations on thefe infeCts, 
and am making fome experiments concerning them, the refult 
of which 1 ffiould be extremely happy in being permitted to 
communicate to you j and it may be proper to add here, that 
1 I ffiould 
