186 INTERNAL ANATOMY OF INSECTS. 
tagonist muscles 8 . In extracting the posterior leg of 
Necrophorus Vespillo I observed more than a single 
pair of muscles that had their attachment in the coxa ; 
and probably many other variations in this respect exist. 
Little was known with respect to the most interesting 
part of the muscular apparatus of insects, that by which 
such wonderfully rapid and varied motions are imparted 
to their organs of flight, till Chabrier undertook to 
elucidate it ; which he has done in a manner that will 
confer a lasting honour upon his name, as one of the 
most able successors to Swammerdam and Lyonet in 
their peculiar department. He has given a most admi- 
rable account of the internal anatomy of the trunk of 
insects in general, as far as it relates to their flight ; 
particularly of that of the cockchafer (Melolontha vul- 
garis), of one of the Libcllulina (JEsJma gra?idis), and 
of a humble-bee (Bombus) ; and I believe he has thus 
illustrated insects of some of the other Orders, but his 
memoirs on these I have not had an opportunity of con- 
sulting. What I have to say on this subject, therefore, 
will be principally derived from what he has communi- 
cated with respect to the above insects. , 
A considerable difference in the volume of the mus- 
cles of the wings takes place in insects according to the 
force of their flight. Where it is rapid and powerful, 
the alitrunk is nearly filled by them, and the alimentary 
canal is much attenuated ; but in those whose flight is 
feeble, they occupy less space, and the alimentary canal 
is proportionally enlarged b . In the Lcpidoptera^ Hy- 
mcnoptera and Diplera, the principal muscles of both 
' Cuv. ubi supr. 459. b Chabr. Snr le Vol dcs Ins. c. i. 441. 
