THE HUMAN-FLEA. 



331 



The eggs hatch in about six days, at least during the 

 warmer part of the year. The white larvse are furnished 

 with feelers and eyes, a very unusual thing in insects. 

 Though without feet they move about very rapidly in a ser- 



Fig. 109. — Mouth-parts of human-flea. After Taschenberg 



pentine fashion; they soon turn yellowish, and later they 

 gradually become brownish. In about eleven'days they are 

 fully grown. They no w form a sort of loose cocoon, composed 

 of particles of dust, inside of which they transform into a 



Fig. 110. — Human-flea. Greatly enlarged. Original. 



pupa, which is at first of a white, but later of a brown 

 color. After ten to twelve days more the adult flea (fig. 110) 

 appears, ready to torment its host, man. In warmer coun- 

 tries the flea passes all these metamorphoses in much shorter 



