92 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
alcohol were much more attractive than others. This was true of honey 
and com syrup. For some unknown reason allyl alcohol mixed with 
water solutions of brown sugar or molasses were not as a rule very 
attractive. 
Upon learning that allyl alcohol was so decidedly attractive the author 
turned his attention to a study of a number of the alcohols. The 
following were tried; allyl alcohol, iso propyl alcohol, ethyl alcohol, 
butylic alcohol, amyl alcohol and methyl alcohol. In a number of re¬ 
peated trials with different media the first five alcohols named proved 
to be more or less attractive for both species. They are named in the 
order of their attractiveness. Methyl alcohol and in some instances, 
amyl alcohol had no attraction for the flies of either species. As a rule 
the alcohols were most attractive when combined with honey as a 
medium. After a few experiments with the attractive alcohols in the 
field it was soon discovered that baits containing these alcohols soon 
lost their attractiveness. This is undoubtedly due to the complete and 
rapid evaporation of the alcohol when placed in the hot sun and dry 
winds. In most cases baits mixed with alcohols did not attract flies 
after 48 hours and in some cases failed to attract after 24 hours. In an 
effort to find some means whereby the attractiveness of the bait could 
be continued over a longer period of time by maintaining a constant 
and new supply of alcohols the author thought of fermentation which 
might be brought about by yeasts. A large number of tests were made 
with yeasts in combination with the several media and in most in¬ 
stances the baits containing yeasts proved to be very attractive to both 
species of flies. Furthermore the yeasts continued to develop the 
attractive odors and in some instances the baits containing yeasts con¬ 
tinued to attract flies for two and three weeks provided water was 
present. 
Two kinds of yeast were experimented with, a hard compact dry 
yeast (“Magic Yeast” or “Yeast Foam”) and a compressed wet yeast 
(“Fleichman’s Yeast”). Small pieces (about the size of a small pea) 
of the respective yeasts were added to each dish of the different media 
employed and within 12 to 48 hours decided gas production was ob¬ 
served in the dishes. As soon as the fermentation odors came off the 
flies of Hylemyia antiquci Meig., and Hylemyia cilicrura Rond., usually 
came to the traps in large numbers. Yeasts mixed with water solutions 
4 
of molasses, honey or brown sugar proved to be the most attractive 
while yeasts combined with water solutions of corn syrup or cane sugar 
were least attractive. The dry yeast baits usually required a longer 
