WINGED INSECTS. 301 



that distinguished entomologist. These muscles 

 are represented in Fig. 144, which has been 

 carefully reduced from his beautifully executed 

 plates. The largest mass of muscular fibres is 

 that marked a, which depress the wings, and 

 are of enormous size and strength. 



On examining the different structures which 

 compose the solid frame-work of insects, we find 

 them conforming in every instance to the ge- 

 neral type of annulose animals, inasmuch as 

 they consist of thickened portions of integu- 

 ment, encircling the body ; but variously united 

 and consolidated, for the manifest purpose of 

 obtaining greater mechanical strength and elas- 

 ticity than if they had remained detached pieces, 

 joined only by membranous connexions. A long 

 flexible body, such as that possessed by the My- 

 riapoda, could not easily have been transported 

 through the air ; for every bend would have 

 created a resistance, and have impeded its ad- 

 vance during flight. Hence the body of the 

 insect, which is to be ultimately adapted to this 

 mode of progression, has been shortened by a 

 reduction in the number of its segments, and 

 rendered more simple and compact. The seg- 

 ments destined to support the wings have been 

 expanded for the purpose of lodging the power- 

 ful muscles that are to move them ; and ren- 

 dered dense and unyielding in order to support 

 their action. 



