98 NATURAL HISTORY OF WASPS. 
This mode of arrangement of the muscles of flight 
obtains generally through all the families of insects. 
A singular exception is found in the dragon-fly,* 
where the muscles are not inserted into the walls of 
the thorax, but pass directly to the root of the wings. 
The muscles of flight are much more elaborately 
developed in this insect than im the wasp, and move- 
ments which are intrusted in the wasp to self-acting 
mechanism are performed in the dragon-fly by special 
muscles. ‘To make room for all these, they are 
tapered off and fitted to tendons at one end, just like 
the muscles of the higher animals. We may readily 
trace their arrangement in a recent specimen, and 
observe the mode of attachment of the muscular 
fibres to the black cups into which the tendons 
expand to receive them. But the specimen must be 
quite fresh; for the least putrefaction loosens all 
their attachments, and the muscular bands become 
undistinguishable from each other. 
The elevators and depressors of the wings are the 
mainspring, so to say, and execute the effective 
movements of the wasp’s flight. But their action is 
supplemented in all its minor details by other smaller 
muscles, strong enough to guide, though not to 
drive, the wings, able to fold or expand them, to 
lock or unlock them at will, and to draw them at 
each moment mto the right position for the stronger 
muscles to act upon them. 
Deferrig the full consideration of the problem of 
* See Bennett, On the Anatomy of the Thorax in Insects, and its 
Functions during Flight, ‘ Zoological Journal,’ Vol. II, p. 891, referring 
to Chabrier, sur le Vol des Insectes, ‘Memoires du Mus. d’Hist. 
Naturelle.’ 
