196 THE HOUSE FLY—DISEASE CARRIER 
lime and spread out in a large tin pan. Two days later 
most of the larvae were found to have hardened into 
puparia, but none was killed. 
September 4th, eight quarts of fresh horse manure 
containing larvae were spread out in a tin pan and 
sprayed with one pint of kerosene washed down with 
one quart of water. September 7th, three days later, 
twenty per cent, of the larvae were still living. 
September 7th, eight quarts of fresh horse manure 
containing house fly larvae were placed in a tin pan, 
sprayed with one pint of kerosene, washed down after¬ 
wards with one quart of water. The manure was then 
mixed and a little more water poured on. Twenty-four 
hours later every larva in the mass was dead. 
October 15th, one pound of chloride of lime was 
mixed with eight quarts of well-infested horse manure, 
which was kept in a bucket. October 16th, ninety per 
cent, of the larvae were dead, the remainder having 
burrowed into the large lumps of manure. October 
18th, no living larvae could be found. 
October 21st, one-quarter of a pound of chloride of 
lime was mixed with eight quarts of fresh horse ma¬ 
nure and kept in a bucket. This treatment was unsuc¬ 
cessful and only two larvae were killed. 
Herms also conducted certain experiments in this 
direction at the University of California. He found 
that the fly larvae are extremely tenacious of life, and 
that insecticides which will kill them must be strong, 
in fact from two to five times as strong as those which 
are useful against other insects. He writes, “Chem- 
