WINGED INSECTS. 215 



tomy of which has l)ccn minutely invcstigntcd l)y that dis- 

 tinguished entomologist. These muscles are represented in 

 Fig. 144, which has heen carefully reduced from his beauti- 

 fully executed plates. The largest mass of muscular fibres 

 is that marked a, which depress the wings, and are of enor- 

 mous 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 general type of annulose animals, inasmuch 

 as they consist of thickened portions of integument, encir- 

 cling the body; but variously united and consolidated, for 

 the manifest purpose of obtaining greater mechanical strength 

 and elasticity than if they had remained detached pieces, 

 joined only by membranous connexions. A long flexible 

 body, such as that possessed by the Myriapoda, 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 segments des- 

 tined to support tiie wings have been expanded for the pur- 

 pose of lodging the powerful muscles that are to move them; 

 and rendered dense and unyielding in order to sup])ort their 

 action. 



Nature has farther provided insects with instruments 

 adapted to different kinds of external actions. They consist 

 of articulated levers, variouslv combined together, and form- 

 ing legs, claws, pincers, oars, palpi, and, lastly, wings, cal- 

 culated for executing every variety of prehension, of pro- 

 gression, or whatever other action their wants and necessities 

 require. 



§ 3. Development of Insects. 



It would appear as if the final accomplishment of objects 

 so numerous, so widely difierent, and so liable to mutual in- 

 terference, could be attained only by the animal being sub- 



