E-N T O M 
src white and tender, though before as hard as bone ; fo 
Tthat the larva, when provoked, will attempt to gnaw 
iron. When the worm a flumes the pupa date, it forms 
with the hinder feet a poliffied cavity, in this it lies for 
fome time immoveable; after which, by voiding excre- 
tnentitious fubflances, and by the evaporation of humidity, 
it becomes thinner and fhorter, the (kin more furrowed and 
wrinkled, fo that it foon appears as if it were ftarved by 
degrees. If it be diffeCled about this period, the head, 
the belly, and the thorax, may be clearly diftinguifhed. 
While fome external and internal parts are changing by a 
flow accretion, others are gently diftended by the force of 
the impelled humours. The body contracting itfelf, 
while the circulating fluid is propelled towards the head, 
forces the fkull open in three parts, and the (kin in the 
middle of the back is feparated by means of an undulat¬ 
ing motion of the incifions of the back ; at the fame time 
the eyes, the horns, the lips, &c. call their exuvia. Dur¬ 
ing this operation, a thin watery humour is diffufed be¬ 
tween the old and new fkin, which renders the reparation 
eafler. The procefs going on gradually, the larva is at 
laft difengaged from its fkin, and the limbs and parts are, 
by a continual unfolding, transformed into the pupa flate ; 
after which, it twills and comprefles the exuvia by the 
fundament, and throws it towards the hinder part under 
the belly. The pupa is at this time very delicate, tender, 
and flexible ; and affords a mofl pleafing appearance to 
an attentive obferver. In it the future parts of the beetle 
are finely exhibited, fo difpofed and formed, as foon to 
be able to ferve the creature in a more perfect flate of life, 
and to put on a more elegant form. 
The pupa of this infeCt weighs, a little after its change, 
much heavier than it does in its beetle flate ; this is alfo 
the cafe with the pupa of the bee and hornet. The latter 
has been found to weigh ten times as much as the hornet 
itfelf; this is probably occafioned by a fuperabundant 
moifture, by which thefe infeCts are maintained and nou- 
rifhed during their torpid flate. Ilovv long the feene of 
mutation continues is not known ; fome remain during 
the whole winter, more particularly thofe which quit the 
larva flate in autumn, when a hidden cold checks their 
further operations, and confequently they remain a pupa 
for feveral months. Some fpecies of the beetle tribe go 
through all the ftages of their exiftence in a feafon, while 
others employ near four years in the procefs, and live as 
winged infeCts a year. 
When the proper time for the final change arrives, all 
the mufcular parts grow flrong, and are thus more able 
to fhakq^off their laft integuments,.which is performed 
exaClly in the fame manner as in the palfage of the infeCt 
from the larva to the pupa flate ; fo that in this laft fkin, 
which is extremely delicate, the traces of the pulmonary 
tubes, that have been pulled off and turned out, again 
become vifible. All parts of the infeCt, and more parti¬ 
cularly the wings and their cafes, are at this period fwel- 
led and extended by the air and fluids which are driven 
into them through the arteries and pulmonary tubes ; the 
v/ings aje now foft as wet paper, and the circulating fluid 
iffues from them on the lead wound ; but when they have 
acquired their proper confiftency, which in the elytra is 
very confiderable, they do not exhibit the leaf! fign of any 
fluid within them, though cut or torn almoft afunaer,—• 
The pupa being difengaged from its fkin, affumes the form 
of a beetle, and acquires a diftinCtion of fex, being either 
male or female. The infeCt now enters on its laft flate of 
exiftence ; raifes itfelf towards the Ikies, plays in the fun- 
beam, propagates its like, depofits the eggs for a new pro¬ 
geny in a f'ecure place, and dies. 
Such is the procefs of the transformation of thofe in- 
feCls whole habitudes confine them to dry land. We 
fhall now deferibethe metamorphofis of an aquatic infeCt, 
the mufea chamaleon. In the worm or larva condition it lives 
in the water, breathes by the tail, and carries its legs 
within a little trunk near its mouth. When the time ar¬ 
rives for its pupa flate, it goes through the change with- 
•V-0L. VI. No. 395, 
O L O G Y. 837‘ 
out calling off the fkin of the larva. But in the imago, or 
fly flate, it would infallibly perifh in the water, was not the 
larva by nature inflrudled how to choofe a fuitab'e fitua- 
tion for its approaching transformation.' The larva of 
this infedt appears to confift of twelve annular divifions ; 
hy thefe it is feparated into a head, thorax, and abdomen ; 
but as the ftomach and inteflines He equally in the thorax 
and abdomen, it is not eafy to diftinguifh rheir limits until 
the infedl approaches the pupa (late. The parts mofl 
worthy of notice, are the tail, and the fnout or trunk.—• 
The tail is furniflied with an elegant circle of bridles, dif¬ 
pofed quite round it in annular form ; by means of this 
the tail is fupported on the furface of the water, while the 
worm or larva is moving therein, the body in the mean¬ 
while hanging towards the bottom in feavch of food. 
When it is difpofed to fink to the bottom, it turns the 
bridles of the tail towards each orher, hollow in the mid¬ 
dle, but clofe towards the extremity; by thefe means a 
conical fpace is formed, and the bladder of air pent up 
in it looks like a pearl. It is by the afliftance of this little 
balloon, that the infeCl raifes itfelf again to the furface. 
If this bubble efcape, it can replace it from the pulmo¬ 
nary tubes ; fometimes large quantities of air may be feen 
to arife in bubbles from the tail of the worm to the fur- 
face of the water, and there mix with the incumbent 
atmofphere. This operation may be eafily feen by placing 
tire worm in a tumbler of water, where it will afford a 
very entertaining fpectacie. The fnout or trunk is di¬ 
vided into three parts, of which that in the middle is im¬ 
moveable ; the two other parts grow from the (ides of 
the former; thefe are moveable, vibrating in a very An¬ 
gular manner, like the tongues of lizards and ferpents. 
The greateft flrength of the animal relides in thefe lateral 
parts of the fnout; it is on thefe that it walks at the bot¬ 
tom of the water, and alfo on dry land ; appearing, as it 
were, to walk on its mouth, and ttfing it as a parrot does 
its beak, to climb with greater advantage. 
Thefe larvae are generally to be found in (hallow (land¬ 
ing waters, about the beginning of June, fooner or later, 
as the fummer is more or lefs favourable. After a certain 
period they pafs into the pupa form. When they are 
about to change, they betake themfelvesto the herbs that 
float on the furface of the water, and creep gently there¬ 
on, till at length they lie partly on the dry furface, and 
partly on the water ; when in the larva or pupa flate, they 
can live in water, but can by no means inhabit there when 
changed into flies. When thefe worms have found a pro¬ 
per (ituation, they by degrees contraCl themfelves, and 
lofe all power ot motion. The inward parts of the 
worm’s tail now feparate from the outer fkin, and be¬ 
come greatly contracted; by this contraction, an empty 
fpace is left, into which the air foon penetrates. Thus 
this infeCt paffes into the pupa flate under its own fkin, 
entirely different from that of the caterpillar. This 
change may often be obferved to take place in the fpace 
of ten or twelve hours; but in what manner it is perform¬ 
ed, or how efl'eCted, is hidden from our view. 
Whilft the larva is thus changing under the fkin, the 
body, the head, and tail, feparate infenfibly from their 
outward veflure. The legs at this time, and their carti¬ 
laginous bones, are, on account of the parts which are 
withdrawn from them, left empty; the worm lofes alfo 
the former fkull, ‘ together with the bones belonging 
thereto, which remain in the fkin of the exuvia. It is 
worthy of notice, that the optic nerves feparate alfo from 
the eyes, and no more perform their office. The mufcles 
of the rings in like manner, and a great part of the pul¬ 
monary points of refpiration, are feparated from the ex¬ 
ternal cuticle. Thus the whole body contracts itfelf by 
degrees into a compaCt mafs. At this time the gullet and 
pulmonary tubes cafl a coat within the fkin. To make 
this evident, it is neceffary to open the abdomen ; when 
the pupa, its parts, together with the caft-off pulmonary 
pipes, may be clearly diftinguifhed. 
When the time approaches that the hidden infeCt is to 
jo D attain 
