CHEMOTROPIC TESTS WITH THE SCREW-WORM FLY 23 
effectively prevented infestation by Cochliomyia even when mixed 
with lubricating oil in 10 per cent solution. 
IODIDES 
Iodoform is a very good repellent, either alone or mixed with 
kaolin or with petrolatum. It is not effective in preventing infesta- 
tion, but no Cochliomyia flies emerged from iodoform-treated meat. 
ALCOHOLS 
Denatured alcohol appears to be slightly attractive to screw-worm 
flies, and dextro-borneol, when dissolved in alcohol, becomes more 
attractive to them. Alpha-terpineol and dextro-borneol are the only 
compounds in this group exhibiting more than a slight repellent 
action. The tests with fusel oil, glycerin, and linalool are inconclu- 
sive, owing to an insufficient number of flies. 
Nearly all of the jars treated with alcohols were infested, but in 
the case of linalool and menthol this was by species other than 
Cochliomyia. 
PHENOLS 
Guaiacol is the most effective compound in this group as a repel- 
lent for screw-worm flies. Its action persists over five days of ex- 
posure. Safrol is effective for the first and second days of exposure, 
but after that it loses its strength. Tests with ortho-cresol and with 
thymol plus pine oil are inconclusive because of an insufficient 
number of flies. 
The phenols are surprisingly poor in preventing infestation. 
While the two jars of meat treated with guaiacol were infested, there 
was no emergence of Cochliomyia from them; neither did any Coch- 
liomyia emerge from thymol-treated meat. 
ALDEHYDES 
Benzaldehyde and furfural are the most effective repellents in this 
group. Cinnamic aldehyde is a good repellent for two days, and 
crotonaldehyde and salicylic aldehyde are effective over a period of 
three days' exposure. The test with formaldehyde mixed with 
petrolatum is inconclusive, as there were almost no flies at that 
time. 
None of the aldehydes are effective in preventing infestation. 
No Cochliomyia emerged from meat treated with formaldehyde, 
crotonaldehyde, citronellal, or furfural, but the emergence data on 
these compounds are meager. 
CHLORINE SUBSTITUTED ALDEHYDES 
Chloral hydrate is of no value in repelling Cochliomyia flies, 
neither does it prevent infestation. 
KETONES 
All of the materials in this group appear valueless both as repellents 
against screw-worm flies, and in preventing infestation. 
