24 BULLETIN 1472, U. S. DEPARTMENT OF AGRICULTURE 
CHLORINE SUBSTITUTED KETONES 
As a group, this is the most effective class of compounds tested, 
both in repellent action and in preventing infestation. The tests 
with chloroacetone in lubricating oil (1 per cent and 10 per cent 
solutions), and with chloroacetophenone in lubricating oil (1 per 
cent and 10 per cent solutions) are inconclusive on account of lack of 
flies. Both chloroacetone and chloroacetophenone when used undi- 
luted not only kept over 99 per cent of the flies away, but also pre- 
vented any emergence of Cochliomyia, and the former compound 
prevented all infestation. 
ACIDS 
Although the number of tests with organic acids is inadequate for 
generalizing, it appears that valeric acid is attractive to screw-worm 
flies. 
ESTERS 
The esters tested appear to be neutral rather than repellent to 
Cochliomyia and do not prevent infestation. 
HALOGEN SUBSTITUTED ESTERS 
Both the beta-chloroethyl and beta-bromoethyl acetates are quite 
effective in repelling screw- worm flies; and both are quite effective in 
preventing infestation, not only in undiluted form, but also in com- 
bination with lubricating oil (10 per cent solution). There was no 
emergence of Cochliomyia from any of the jars treated with these 
compounds. The bromo compound is a more effective repellent 
than the chloro compound. This is in harmony with the results 
obtained with para-xylyl chloride and para-xylyl bromide. 
ETHERS 
Beta-naphthylethyl ether is a very good repellent for use against 
screw-worm flies, being effective over four days' exposure. The tests 
with this compound mixed with petrolatum and with mineral oil were 
made when an insufficient number of flies was present for an accurate 
result. Beta-naphthylethyl ether does not prevent infestation. 
There was no emergence of Cochliomyia from these jars. 
CHLOROHYDRINS 
Only one compound belonging to this group, namely epichloro- 
hydrin, was tested, and though very few flies were available at the 
time of the test, the compound exhibits no worth-while repellent 
action; neither does it prevent infestation. 
NITRO COMPOUNDS 
Nitrobenzene and alpha-nitronaphthalene were good repellents over 
the entire period of the test. Nitrocymene is an excellent repellent 
during the first two days' exposure, but loses its effectiveness on the 
third day. In preventing infestation, all the nitro compounds show 
up poorly. The emergence data with this group of compounds are 
incomplete, but no Cochliomyia emerged from meat treated with 
nitrobenzene. 
