PROGRESSIVE MOTION OF INSECTS. 307 



Fig. 158*) are the burrowing implements, and they 



158* ^^m^ ^^^ admirably calculated 



for their peculiar office, 

 both in their shape and in 

 the mode of articulation 

 of their several divisions, 

 which bear a considerable analogy to the corre- 

 sponding member of the mole. Dr. Kidd observes, 

 that, compared with the other legs, and with the 

 general size of the animal, they are as if the brawny 

 hand and arm of a robust dwarf were set on the 

 body of a delicate infant ; and the indications of 

 strength which their structure manifests, fully 

 answer to their extraordinary size.* 



Examples without number might be given of 

 similar mechanical adaptations of the limbs of in- 

 sects to the performance of particular actions re- 

 quired by the peculiar circumstances of their con- 

 dition : such as the construction of the anterior legs 

 of the Scaritidce, which, like those just described, 

 are excellent implements for burrowing ; of those 

 of the Mantis, admirably formed for prehension ; 

 and of the hind legs of the Gyrinus, expressly 

 adapted to their singular rotatory mode of swim- 

 ming : but the limits of this work necessarily re- 

 strain me from entering into so many details of 

 minute structure, and expatiating in so immense a 

 field of entomological inquiry. 



* For a more particular description of tlie mechanism of this 

 instrument, I must refer the reader to the paper above quoted. 



