392 



INSECT TRA.NSFOIIMATIONS. 



creature is well fitted for its mode of life — it being 

 furnished with so tough a skin that it is no easy 

 matter to crush it, while it is so smooth that it would 

 almost glide through a pin-hole. The extraordn:iary 

 muscular power of the thighs, again, combined with 

 their elasticity, enables it to perform most astonishing 

 leaps, as we have remarked in a preceding page ; 

 while its comparative lightness and the toughness of 

 its skin prevent it from receiving any injury, from 

 whatever height it may fall. It is very doubtful, 

 indeed, as it appears to us, whether it observes the 

 good old proverb of looking before it leaps, for we 

 have seen fleas leap from the bottom of a deep pill- 

 box, where they could not possibly perceive w^hither 

 they were leaping.* It may not be out of place here to 

 mention, that fleas (Pulicidce) undergo similar trans- 

 formations to other insects, laying their eggs at the 

 roots of the hair of animals, the feathers of birds, or 

 in woollen stuff's. These, in a few days, produce a 

 minute whitish grub, which, in warm weather, 

 changes to a perfect flea in about six weeks : as may 

 be verified by whoever will take the trouble of en- 

 closing some female fleas, which are always the 

 largest, in glass tubes, and feeding them with flies or 

 raw beef, as was done by Rosel, De Geer, and many 



Flea magnified, to show the muscuUr stjucture of the le; 

 * * J. R. 



