NATURAL ENEMIES 
85 
is true that the larvae of certain Carabaeid beetles, and 
especially those of the genera Harpalus, Platynus and 
Agonoderus, are sometimes found frequenting manure 
and feeding upon young fly larvae, and that certain 
rove beetles and their larvae, of the family Staphylinidae, 
are also found in the same situations, engaged in the 
same task. And Packard (1874) records the finding 
of a beetle pupa in'the puparium of the house fly. But 
one would think that a pile of horse manure swarming 
with fly larvae would attract hordes of predatory beetles 
and of pirate bugs and the like. Is it that house fly 
maggots are distasteful to these voracious creatures? 
Or is their perception of odors keen and are the am- 
moniacal odors of the manure pile repugnant? It is 
difficult to say. The typhoid fly belongs plainly to a 
most persistent type, and it feeds freely and abundantly 
in close proximity to many insects which we would 
naturally suppose to be its enemies. 
But we must not forget the ants. It is true that 
many ants are nuisances, and in the case of the destruc¬ 
tion of the typhoid fly by ants we have simply one nui¬ 
sance multiplying at the expense of another, but Forel 
and Wheeler admit that as a group ants are beneficial 
and that many species deserve our protection. Capt. 
P. L. Jones of the U. S. Army Medical Corps (quoted 
by Garrison, U. S. Naval Med. Bull., Oct., 1910, p. 
551) made certain experiments in the Philippines to 
determine whether the scarcity of flies in those islands 
was due to some epidemic disease. In the course of 
the experiments it was found impossible to raise flies 
