The Two-winged Flies 
357 
will keep them down. Mats and places where dogs and cats lie down should 
be kept well dusted with pyre thrum. (Buhach is the trade name for this 
insecticide, which is not injurious to man or domestic animals.) Where 
fleas get a foothold in a neglected room or cellar, the remedy used by Profes¬ 
sor Gage in the basement of one of Cornell University’s buildings might be 
tried; i.e., tying sheets of sticky fly-paper, sticky side out, around the legs 
from foot to knee of the janitor or a cheap boy and having him tramp for 
several hours around in the room! 
Of the various other flea species, the only ones that come into special 
relation with man are the rat-fleas. The proof that rats are active agents 
in the dissemination of the dreadful bubonic plague, and the belief of some 
pathologists that the disease-germs may be transmitted from rats to man 
by the bites or punctures of rat-fleas, gives this insect a special interest like 
that attaching to the malaria- and yellow-fever-dissminating mosquito and 
the germ-carrying house-fly. Baker pertinently calls attention to the fact 
that the rat-fleas of this country are only remotely related to Pulex irritans 
and Ctenocephalus cams , the two species that bite human beings, while the 
fleas that infest rats in the tropics are, on the contrary, very nearly related to 
the man-infesting kinds. The prevalence of the bubonic plague in tropical 
countries and its rarity with us may be connected with this difference in the 
rat-flea kinds. 
