492 
THE STUD Y OF INSECTS . 
burned, and the floors wet with kerosene emulsion or some 
other insecticide that will destroy the eggs and larvae. 
In regions where fleas abound much relief can be ob¬ 
tained by the use of rugs on the floors of dwellings instead 
of carpets. The frequent shaking of the rugs and cleaning 
of the floors will prevent the breeding of these pests within 
the house. As a single flea will inflict many bites, it often 
happens that a house will seem to be overrun by them when 
only a few are present. In such cases a careful search for 
and capture of the offenders will soon remedy the evil. We 
have found that in catching fleas greater success attends our 
efforts if the thumb and forefinger be wet before seizing the 
flea, and the insect be placed in a dish of water before we 
attempt to destroy it. Otherwise the insect is apt to escape 
while we are trying to destroy it. 
People that suffer from the attacks of these pests can 
also gain much relief by dusting the upper part of their 
stockings each morning with Persian insect powder, and by 
sprinkling a small quantity of this powder between the 
sheets of their beds at night. 
This order contains only a single family, the Pulicidce 
(Pu-lic'i-dae), of which five or six genera and about twenty- 
five species are now known. The species that are most fre¬ 
quently observed are the following :— 
The Dog-flea, Ceratopsyllus serraticeps (Cer-a-to-psyl'lus 
ser-rat'i-ceps).—This is the most common flea that infests 
dog, cat, and man in this country (Fig. 598). It is reddish 
brown ; the lower margin of the head and the hinder margin 
of the prothorax each bear on each side from seven to nine 
black, tooth-like spines. 
The Human-flea, Pulex irritans (Pu'lex ir-ri'tans). This 
species lacks the comb-like rows of black spines on the lower 
side of the head and on the hinder margin of the prothorax. 
It is also usually darker than the preceding species, being 
sometimes pitchy brown. It is a common pest in dwellings 
in Europe, but is comparatively rare in this country. 
