-6- 
not so satisfactory as is combined arsenic-carbolic, which has greater lasting 
properties. 
Recent experiments macb "by Stewart (142) in IT o r thumb er land, England, 
suggest that derris powder applied as a dry dust to the fleeces of youn- lambc 
is an effective tick deterrent, with obvious advantages over dips in. that it 
is less troublesome to apply and less likely to cause mis— mothering. Stewart 
( 143 ) in 1939 reported on the control of the British sheep tick in Scotland. 
Di-<s and dusts were tested. The following dips were used: A plain derris dip; 
derris— carbolic dip; derris-carbolic-woolfat dip; arsenic-carbolic dip; and 
arsenic-derris dip. Two methods of rendering lambs tick-free have been tried, 
and the method of choice appeared to be the use of a powdered preparation cf 
derris roct. The dustinc is quickly and easily carried out, produces no ill 
effects, and dusted lambs remain remarkably tick-free for more than 2 weeks. 
An oily smear also proved useful. It checked tick infestation, and smeared 
lambs were more thrifty and on the average 10 pounds heavier than the corres- 
ponding unsmesred lambs. As a result of the failure of the derris dips to • 
protect sheep under field conditions, the derris-carbolic and the derris 
-carbolic— wo olf at dips were discarded at the second dipping on May 5 and the 
plain derris and the arsenic-derris dips were substituted. The arsenic-car- 
bolic dip showed only moderate protection. The most satisfactory dip proved 
to be arsenic-derris, which showed a marked deterrent effect 2 weeks after use. 
Mironoff et al. ( 106 ) in 1940 reported that larvae of Ixodes ricinus were 
killed in 1/2 to 1 hour by derris powder. The nymphs were killed in 1/2 hcur, 
but the mature ticks ^ere more resistant. 
R hinicephalus sanguineus ' (Latr 6 .)-» the brown dog tick 
Little ( 93 ) in 1931 re-ported that the powdered root of both Teohrosia 
Virginians and derris were unsatisfactory in the control of the brown, dog tick. 
In 1931 Bishopp (8_) recommended powdered derris root, either dry or as a 
wash, for combating the brown dog tick on dogs. 
i/iarney (98) in 1932 wrote that a powder containing 1 percent of rotenone, 
when dusted on a do-<? infested with the brown dog tick, killed the parasites 
within 24 hours and prevented reinf estation for 10 days or more. 
The United States Department of Agriculture, Bureau of Entomology ( 149 ), 
in 1933 reported that for combating the brown dog tick, a severe pest of d 
in Texas and Florida, the use of derris and derris derivatives on the dogs and 
in their sleeping places, together with the application of insecticidal sprays 
on the walls of the infested rooms, had given satisfactory control. 
Ross (130) in 1935 reported that, from dog owners' reports, derris 
preparations appeared to be effective against Rhipicephalus sanguineus , the 
dog tick of central Queensland", and that weekly .application, either of derris 
powder in dry form or of a 1-percent soapy cold-water infusion, should confer 
a high measure of protection 8gainst tick infestation. Derris must be applied 
