The: (HA S PO. RE Yosobrl NGS yes. 
are hollow, fomewhat fwollen, and expanded to 
an elliptical igure, and are fomewhat {welled or 
blown up, Tab. XXIX. fig. 1x. aa, by force of 
the air impelled into them. . Thete is likewife 
this confiderable difference, that out of the ends 
of thefe veficles, where they reft upon their 
hollow pulmonary tubes, other pipes and ra- 
mifications 64 again break out Jaterally, which, 
after they have been again dilated into veficles, 
form air branches, veficles and pipes: fo that 
this divifion and procefs continues, until at 
length they terminate in very delicate, and ‘as 
it were invifible pulmonary paflages, which 
always remain round with open cavities. Hence 
the ftructure that occurs here may not be 
improperly compared to the third fpecies of 
the Sea Wrack of Dodoneus. Nay, it is 
likewife obferved that many tubes of this 
kind fometimes iflue cc out of the fame veficle, 
which I have reprefented magnified above its 
natural bignefs. Whenever the air gets out 
of thefe veficles or bladders, they fall and be- 
come flat, and by the mutual contact of their 
fides, form a plain fubftance like the {mooth 
leaf of a tree; whilf in the mean time the 
tubes affixed to them always remain open. 
The reafon of this is, becaufe thefe little 
branches rifing from the principal air veffels 
confift of contorted and {piral parts, which, 
like the rings, made of filver thread or wire, 
and twifted round a {mall cylinder, always 
preferve their roundnefs. In the fame man- 
ner this filvery web of pulmonary tubes ap- 
pear to me to be compounded of a horny 
or bony pellucid matter, white as mother of 
pearl, and wound into fpirals. Thefe tubes are 
likewife lined on their infide with very deli- 
cate membranes, which keep their {piral form 
with ali its windings in their fituation. But 
where they are dilated into pneumatic veffels, 
they are entirely membranaceous, and befides, 
when viewed with a powerful microfcope, are 
obferved to be planted or fet there with {mall 
ftuds or boffes like little grains. This is in- 
deed a very agreeable obje@. Moreover, thefe 
veficles are of a palith or white colour, and 
having no polith are nearly of the afpect of a 
Spider-web, or any thing of a like kind, co- 
vered with duit. The tubes on the other 
hand, are bright and {plendid, and of a filver 
or of a pearly colour. See the explanation of 
thefe in Tab. XXIX. fig. x. 
The reafon of this difference between the 
pulmonary tubes of this creature, while it is 
inthe Worm, and when it arrives at the Beetle 
ftate, feems to lie in the repeated change of 
their skin, whereof I have made mention be- 
fore. ‘The fame thing is in fome meafure ob- 
ferved in the pulmonary pipes of the Silkworm 
Butterfly, for in this the tubes of the lungs, 
becaufe they many times caft thefe internal 
skins, are every where very much dilated ; 
though they have no diftinét veficles. How- 
ever the matter be, fince thefe white little parts, 
which are feen in the fat of the Nymph, 
ought to come principally into confideration 
70 
here, I think this difficulty may be at length 
folved, if there were fome more diffections 
made for that purpofe. But I muft referve 
the doing of this to another time, and fhall, 
till then, leave this matter uncertain. One 
‘may conveniently inflate or blow up the pul- 
monary tubes of the Beetle before defcribed 
with a flexible leaden pipe, or the quill of the 
wing of forme {mall bird: what in Holland we 
call the Cheefe-bird has feathers admirably 
{uited for this purpofe; for the quills of this 
bird’s wingsare very perfectly hollowed through- 
out, efpecially if they be firft ftrengthened bya 
{mall glafs tube ; and thefe parts thus diftend- 
ed afford a very beautiful fight. 
Any one may fee the pneumatic veffels, to- 
gether with their tubes, without any diffeCtion, 
provided he removes or takes the external 
wings, called the cafes of the wings, from the 
body, and views them when turned to the 
light with a microfcope. They even appear 
through the abdomen of the Beetle, and they 
may be likewife feen in the horny or bony 
and membranous part which covers the lower 
part of the body: but they are prefented in 
the moft beautiful manner between the plates 
of the external wings; for there they form in+ 
numerable and moft fingular figures. Three 
confiderable branches of the wind-pipe com- 
monly appear between thefe cafes, that is, two 
on each fide, and a third fhorter in the middle ; 
and out of thefe one may afterwards fee the 
ref{piratory veficles beautifully iffuing arid placed 
between them, in the fame mannér as I ex- 
hibit them here in a minute portion of that 
part; wherein two larger branches of the tra- 
chea, Tab. XXX. fig. 1. aa, are reprefented 
on each fide, and between them the pulmo- 
nary pipes iffuing therefrom, together with 
their veficles 5454, out of which other pulmo- 
hary pipes arife, which are again dilated into 
veficles cccc; and thefe are again attenuated 
into pulmonary pipes, until at length they end 
in moft minute and invifible filaments. In 
the inner part of the oufer wings there may 
be alfo obferved fome other {mall points, pro- 
jecting beyond the furface of the cafe or theath, 
out of the middle of which iffue oblong dif- 
perfed hairs. Thefe Iam confident are placed 
here to prevent the fubjacent wing from being 
too much preffed, and at the fame time to 
give it the means to fold and hide itelf the 
more eafily under the theath. We have be- 
fore fhewn the ufe of thefe numerous tubes 
and pulmonary bladders; which is, that by 
their help the outer wings or cafes of the win gs 
may be expanded. I would likewife have it 
obferved, that all thefe veficles or bladders 
appear fornewhat fmooth, which may proba- 
bly be owing to the contraction of the theath 
or cafes, which ‘happens when the humours 
are exhaled, and the blood-veffels are clofed or 
fhut up. we 
The heart is much fhorter in the Rhino- 
ceros Beetle which I arm defcribing, than it 
was in the Worm or Coffus; it is likewife 
Q4g more 
