JlIUSCULAR SYSTEM, 
73 
found that besides those that belong to the spiracles, 
the muscles concerned in the function of respiration 
included those of each entire segment of the body. 
Every act of inspiration was of a mixed character, and 
was partly voluntary and partly involuntary. 
Voluntary muscular action is that which depends 
on the exertion of the will of the insect, and involun- 
tary that which is independent of such will. 
Every act of expiration is more of an involuntary 
character, and may be regarded simply as a disposi- 
tion in the muscles concerned to regain their previous 
condition, which is intermediate between contraction 
and relaxation, and takes place independently of the 
will of the insect (Newport). 
Eor instance, the muscular actions of the dorsal 
vessel and the stomach are involuntary, whilst those 
of the jaws and wings are voluntary. 
It would be impossible, within the limits of this 
work, to describe all the muscles, and we must con- 
tent ourselves with saying that there is not a move- 
ment in the body of the bee but is actuated by them. 
