44. The BOO K 
commit miftakes; for, as he had no experience 
of his own to go by, he was obliged to take 
things upon truft from other writers, and confe- 
quently was liable to adopt their errors. 
I muft, on this occafion, defire my readers to 
take notice, that in nty general hiftory of infects, 
I forgot myfelf fo far as to defcribe the Afilus, 
under the name of Tabanus; nor can I account 
for this overfight, as I then made ufe of the 
words of Ariftotle juft now cited. After this 
preface and remark, I fhall briefly defcribe the 
little creature, from which our Afilus or Gad- 
fly proceeds. It is reprefented in Figure 1. 
of Tab. XXXIX. its Nymph in the 11 and 
11 Figure of Tab, XLI. and laftly, the Afilus 
Fly itfelf, in the 11 Figure, Tab. XLII. 
There are feveral very uncommon particulars 
in thefe {tates of the fame infe€ts in the Worm 
condition ; it lives in the water, breathes by its 
tail, and carries its legs within a little fnout near 
its mouth. When it becomes a Nymph, it per- 
forms the change without cafting its fkin; and 
when it becomes a Fly, it can no longer live in 
the water; fo that the element, which hitherto 
fupplied it with life and motion, would now be 
its immediate deftruction. - 
Thefe are all no more than the external won- 
ders; and they appear infignificant, when com- 
pared with the hidden changes and tranfpofi- 
tions of parts, performed within the skin, fto- 
CR 
off NA TURE; or, 
mach and inteftines, but above all, in the fpinal 
marrow, which it is impoflible to fee, without 
being loft in aftonifhment. 
There occur befides in this treble, though at 
the fame time Gingle, little creature, other parti- 
culars, furpaffing, in a manner, all human ima- 
gination ; fuch as its moft uncommon alterations 
of colour, indurations of parts, lofles of limbs, 
and acquifitions of internal organs. 
Thus I fhall clofe. this fhort introduction, 
but I cannot too often remind my readers, 
that they will here meet with a colleGion 
of wonders, any fingle one of which, is worth 
their moft perfect attention. Nor are they the 
lines only of an Apelles, that I defcribe in this 
place, but inimitable pi@ures, and the very han- 
dy-work of the great Creator, God himfelf, to 
whom we are indebted alfo for all that we have, 
of are, and whom we ought to acknowledge in 
the humbleft manner, as our Creator, Preferver, 
and conftant Benefactor. Hence, judge, O man, 
how incomparable mutt be the elegance of thofe 
miracles of his, which fhall never perifh, when 
fo much art and contrivance is to be feen, even 
in the corrupt nature of creatures, that are buried, 
as it were, under darknefs, by his great ordina- 
tions. ‘Therefore to this all-good, all-wife, and 
all-powerful Being, and to him only, be all the 
honour and glory of the prefent difcovery. 
ie 
The external figure of the Worm, from which the Mufca Afilus, or Gadfly, is pro- 
duced, reprefented in its natural bigne/s edie alfo as it appears when magnified 
by the microfcope,; with the manner of its carrying its legs, by a moft wonderful 
contrivance, in its mouth; and of its breathing by the tail. 
TL CoB TT Gare ae 
HIS Worm, viewed with the naked 
eye, appears to confift of twelve annu- 
lar divifions, a, by which it is feparated into a 
head, thorax, and belly; but as the ftomach 
and inteftines lie equally in the two, the thorax 
and belly, their bounds are fcarce perceivable, 
until the infe@, ftill cloathed in the Worm’s 
fkin, approaches the Nymph-ftate. 
The parts moft worthy of notice, that the 
naked eye can difcern in this Worm, are its 
tail and its fnout. The tail is furnifhed with 
an elegant crown 4 or circle of hair, difpofed 
- quite round it in an almoft annular form; by 
means of which, while the Worm moves itfelf 
in the water, this tail can fupport itfelf on the 
furface, the body all the time hanging down 
towards the bottom ; and fometimes it remains 
thus a long while, without the leaft fenfible 
motion. The fnout is divided, as it were, into 
the three parts, c, of which that in the middle 
is altogether immoveable; whereas the two 
others, which grow at the fides of the former, 
vibrate in a very fingular manner, and, in ap- 
pearance, are very like the tongues of Lizards 
and Serpents. The greateft ftrength of the 
5 
Worm is likewife feated in thefe lateral parts 
of its fnout: it is by means of thefe it crawls, 
when out of the water, fo that one would ~ 
imagine it walked with its mouth. Parrots, 
whofe upper and.under jaws are both move- 
able, enjoy, in the fame manner, the privilege 
of ufing their beaks with fuch force, in climb- 
ing, that they have the greateft advantage from 
it. In the fame manner this Worm, as often 
as it can lay hold of any thing with thofe parts 
that Ihave been {peaking of, appears to move, 
as it were, entirely by the help of its fnout. 
Thefe parts, however, do not conftitute its 
mouth, as I {hall prefently fhew. 
When the Worm, being thus fupported on 
the furface of the Water by means of its tail, 
has a mind to fink to the bottom, it generally 
bends the hairs of that part a little towards 
each other in the middle, and much more 
forcibly at the extremities, without difturbing 
them in the leaft about the roots. By this 
means a hollow is formed ; and the air, pent 
up in it, looks like a pearl, Tab. XX XIX. Fig. 
i. a. It is by the help of this bubble that 
the infe@ can again gently raife itfelf to the 
furface of the water, and there remain fuf- 
pended. 
