The last material has been cleared in pharmacological tests for use on 
the skin. Such tests with 2,5,7-trimethyl-3-octyne-2,5-diol were incon- 
clusive, and the other four compounds were rejected because of toxicity 
or skin irritation. 
The repellent times obtainedwith the standards during different field 
trips are shown in table 2. Ethyl hexanediol and mixture 6-2-2 were 
about equally effective and superior to dimethyl phthalate and Indalone, 
which were about equally effective. In only one field trip, on July 11-14, 
1944, was ethyl hexanediol greatly superior to mixture 6-2-2; however, 
only two tests were made with ethyl hexanediol. If the range of the 
average repellent times is compared, mixture 6-2-2 is superior to the 
other standards, with a range of 326 to 161 minutes, giving a ratio of 
2.02 as compared with 3.82 for ethyl hexanediol, 5.24 for dimethyl 
phthalate, and 7.24 for Indalone. 
When pyrethrins or N-isobutylundecenamide or both were added to 
Indalone, ethyl hexanediol, or the ethylene glycol ether of pinene, they 
had practically no repellent value (table 3). Although 1 percent of 
_ pyrethrins in Indalone and 0.5 percent in the ethylene glycol ether of 
pinene gave higher repellent times than the repellents without the 
pyrethrins, the differences were not statistically significant. The 
addition of N-isobutylundecenamide, either alone or with the pyrethrins, 
reduced the average repellent time. 
Most of the mixtures of repellents that were tested in the field were 
superior to the standard (table 4). Only three mixtures had repellent 
ratios less than 90--dimethyl phthalate plus ethyl hexanediol; 2-phenyl- 
cyclohexanol plus 3,4-diethoxybenzaldehyde; and cyclohexyl benzoate 
plus anisyl alcohol. 
The addition of such thickeners as cellulose acetate, ethyl cellulose, 
methyl cellulose, nitrocellulose, colloidal silica, magnesium, zinc and 
calcium stearates, a synthetic gum, and the ethyl ester of o-benzoylbenzoic 
acid failed to increase the repellent time consistently. 
In a series of paired tests with various creams and liquids containing 
volatile solvents and either dimethyl phthalate or a mixture of 2-phenyl- 
cyclohexanol and 1,2,3,4-tetrahydro-2-naphthol, the creams were found 
to be superior to the liquid preparations (table 5). All the preparations 
containing 2-phenylcyclohexanol and 1,2,3,4-tetrahydro-2-naphthol were 
superior to those containing dimethyl phthalate. Dimethyl phthalate was 
more effective in a zinc oxide paste cream than in a cream containing 
bentonite and calcium stearate; however, this cream was less effective 
than a vanishing cream containing the same repellent. 
Some of the more promising powder-base creams tested in the lab- 
oratory against aegypti (Travis et al. 3) were tested in the field against 
taeniorhynchus (table 6). Those prepared with pyrophyllite or tricalcium 
phosphate were considerably less effective than the standard repellent. 
This was also true of creams prepared with bentonite except the one 
