FLEAS AS PESTS TO MAN AND ANIMALS. 5 
The conditions which give rise to outbreaks in houses, particularly 
in the case of the dog flea, are usually these: Pet dogs or cats are 
kept about the household during the spring and early summer, 
and great numbers of eggs are deposited upon them by the fleas. 
These eggs are scattered about the floors and soon hatch into minute 
maggots which feed upon the vegetable and animal matter under 
carpets and mattings and in cracks. During this time the house has 
been closed up and the breeding allowed to proceed unmolested, so 
that at about the time the occupants return the fleas have reached 
Wie. 3.—The human flea: Adult female. Greatly enlarged. (Author's illustration.) 
the adult stage. In the absence of other hosts they are exceedingly 
hungry and ready to attack man or any animals which are accessible. 
Some infestations of residences come from breeding places beneath 
the houses. The fleas in these cases are usually furnished by stray 
animals which sleep under the buildings. The immature stages 
develop in the accumulation of dust and vegetdble matter in the 
beds of these animals. Instances are not uncommon where such in- 
festations may extend to lawns, barnyards, and, in fact, all over the 
premises, although as a rule the center of infestation is in some one 
definite place frequented by animals. 
