392 INSECT TRANSFORMATIONS. 



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

 nished 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 extraordinary muscular power 

 of the thighs, again, combined with their elasticity, en- 

 able 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 

 whither they were leaping.* It may not be out of 

 place here to mention, that fleas {Piilicidai) undergo 

 similar transformations to other insects, laying their 

 eggs at the roots of the hair of animals, the feathers of 

 birds, or in woollen stuffs. These, in a few days, pro- 

 duce 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 muscular structure of the legs. 

 * J. R. 



