NATURAL ENEMIES 87 
and who have made special studies of its habits. The 
reply from each was the same in its general tone. 
Professor Newell never found the Argentine ant 
nesting in pure horse manure, but has found them in 
manure that contained a large amount of straw or hay. 
A certain public dumping ground carrying much ma¬ 
nure was heavily infested with the ants, but house flies 
bred from it in such enormous numbers that the health 
officer was called in. The observer found colonies of 
ants on the ground and also an abundance of fly larvae. 
His experience has been that house flies are not notice¬ 
ably reduced in places where the Argentine ant swarms. 
Professor Garrett writes that the mess hall in which 
about 300 of the students take their meals is in a lo¬ 
cality where the ants are very abundant, and yet the 
house flies are apparently as numerous as ever. He 
thinks that the ants do destroy quite a number of lar¬ 
vae in manure, but that they do not use them as an 
article of food to a sufficient extent to cause an appre¬ 
ciable decrease. Mr. Barber is of the same opinion. 
Mr. F. C. Pratt, an agent of the Bureau of Entomol¬ 
ogy, located at Sabinal, Texas, made an especial study 
of fly larvae at Dallas on one occasion. He found that 
the fire ant, on one occasion when he was experiment¬ 
ing with cow manure in order to raise parasites of the 
horn fly, took complete possession of his rearing cages 
and their contents. In his opinion, they feed upon all 
fly larvae. 
Aside from ants, there are other predatory insect ene¬ 
mies of flies not yet mentioned. Wasps catch house 
