INTERNAL ANATOMY OF INSECTS. 87 
all his attention could perceive no motion in it a . Reau- 
mur also fancied he perceived in the grub of Musca 
vomitoria, in which he in vain looked for the dorsal ves- 
sel, a fleshy part which exhibited alternate pulsations ; 
and when with a pair of scissors he made a lateral in- 
cision in the insect, amongst other parts that came out, 
there was one that had movements of contraction and 
dilatation for several minutes, — this experiment was re- 
peated with the same result upon several grubs b . De 
Geer, whose love of truth and accuracy no one will call 
in question, saw the appearance of blood-vessels in the 
leg of the larva of a Phryganea L. (as Lyonet did in 
those of a flea c ) ; and in the transparent thigh of Orni- 
tJiomia avicularia he discovered a pulse like that of an 
artery d . Baker, whose only object was to record what 
he saw, speaks of the current of the blood being remark- 
ably visible in the legs of some small bugs e : what he 
meant by that term is uncertain, but they could not be 
spiders, which he had just distinguished. This author 
has likewise seen a green fluid passing through the ves- 
sels of the wings of grasshoppers f ; and M. Chabrier is 
of opinion that insects possess the power of propelling a 
fluid into the nervures of their wings and withdrawing it 
at pleasure, as they are elevated or depressed s ; but this 
last fact may be independent of a circulation. 
But though these arguments, which I have stated in 
their full force, appear strong, and at first sight conclu- 
a Bonnet ii. 3;'.). Perhaps in both cases the alimentary canal was 
the organ seen. 
b Reaum. iv. 171 — • c Lesser L. ii. 84. note. 
' Dc Geer ii. 505—. vi. 287. ' On the Microscope, i. 130. 
f Rid. ■ Sur le Vol des Ins. 325—. 
