THE PULEX IRRITANS. 



38s 



sornetimcs twice or three times larger than usual, are found upon 

 the shores frequented by bathers, but they are of the same kind 

 as that which attacks the human race. Fleas lay their eggs in 

 cracks, in cushions, and in boards, or in the midst of dust, and 

 their larvse, which have no legs, and which, therefore, must live 

 where they have been born, can only exist in consequence of 

 the nourishment brought to them by the adults. Were they 

 abandoned they would perish, but they have excellent mothers 

 who never leave them ; for after a flea, should it be a mother, 

 has gorged itself with blood it seeks its young and disgorges a 

 small quantity so as to keep them alive. 



THE METAMORPHOSES OF THE COMMON FLEA. [Pult'X i)-ritans.) 



The larvae shut themselves up in silken cocoons when they 

 have attained their full size, and undergo their metamorphosis 

 into the condition of nymphs. In the engraving the long, legless, 

 vermiform larva may be seen close to an inactive nymph, which 

 resembles somewhat the perfect insect, which has long legs and 

 the peculiar hairiness of the segments. The dog's flea {Pulex 

 canis) is smaller than the species which attacks man, and is 

 distinct from it, nevertheless it sometimes interferes with human 

 beings. The Jigger, or Piclex penetrans, which lives in the hot 

 districts of America, introduces itself under the skin of men and 

 animals, and grows there to a surprising size ; it is very small 

 when it is born. The male always retains its tiny size, and does 

 not shut itself up for life ; but the female attains an immense 

 size when underneath the skin, growing sometimes as large as a 

 nut, on account of the dilatation of the abdomen by the abundance 



