9 G 
DIPTERA. 
the thighs thick and strong, forming admirable leaping 
organs. The larva of the flea is a long footless grub 
with a horny head. Fleas lay their eggs in cracks in 
the boards of rooms, in dust, or other undisturbed 
places; but those species, which are parasitic on dogs, 
cats, squirrels, and moles, lay the eggs amongst the 
hair, and the larvm feed on minute particles of animal 
matter. In about a fortnight the larvse are full grown, 
they then shut themselves up in silken cocoons and 
change to pupae, in which condition they remain for 
about another fortnight, when the perfect insects ap¬ 
pear. Animals have their own peculiar species of 
flea-parasites, but the species belonging to one will 
sometimes attack another. The dog-flea (Pulex canis ), 
for instance, is smaller than the human-flea, and is a 
distinct species, yet it will attack men ; the same may 
be said of the P. gallincc , so common in hens’ nests. 
The flea that infests the squirrel is one of the largest 
with which I am acquainted, but that of the badger is 
larger still. The Jigger or Chigoe {Pulex penetrans) of 
the West Indies and North America inserts itself be¬ 
neath the skin or under the nails of the foot. Here the 
female develops her eggs in the ovaries until she 
becomes as large as a pea; if the pest is not ex¬ 
tracted, it produces ulcerations, giving much pain and 
trouble. 
Idle great security against annoyance from fleas is 
cleanliness; various plants have been supposed to be 
efficacious in driving away fleas, such as Prigeron, Conyza y 
Pulicaria , etc., to which the term “flea-bane” has been 
applied. Old Tusser recommends cleanliness and worm- 
