- 12 — 
INSECTS AFFECTING MAN AND ANIMALS 
Myiasis further reduced by flytraps.—- In the March 1933 Monthly 
Letter the percentage reduction in the screw-worm fly population and 
in attendant cases of myiasis in Dallas County, Texas, and adjoining 
counties in 1932 through the use of flytraps was noted. H. E. Parish 
now reports: "The number of cases of myiasis recorded in 122,334 ani- 
mals of all classes in the trapped area during the month (August) amounted 
to 261, or an infestation of 0.2133 percent. In 69,565 animals of all 
classes in the control area the number of cases recorded amounted to 
355, or an infestation of 0.4815 percent. The percentage infestation 
as recorded in each of the two areas indicates a reduction of 55.7 per— 
cent in the number of screw-worm cases in the trapped area as compared 
to the control area, * * * The semimonthly records of the relative fly 
abundance in the trapped and control areas, as determined by the jar 
method, indicate that a reduction of the total fly population in the trap— 
ped area amounted to 88.02 percent on August 3 and to 93.87 percent on 
August 18. These records show also that in the trapped area the re— 
duction of the screw-—worm fly (Cochliomyia macellaria Fab.), which com— 
posed from 90.5 to 96.1 percent of the total of all species of blowflies 
present, amounted to 91.38 percent on August 3 and to 95.64 percent on 
August 18, as compared to the abundance of this species in the control 
area, * * * a fine example of the efficiency that may be obtained by the 
systematic operation of flytraps over large areas." 
sulphides increase efficiency of blowfly baits.--E. W. Laake, Dal- 
las and Menard, Tex,, reports that "Experiments conducted during the 
month (August) indicate that the addition of 1 percent solutions of 
Sodium and potassium sulphide instead of water for replacing the quantity 
of liquid lost from meat baits through evaporation increases the catch 
over 100 percent and also increases the longevity of meat baits con— 
Siderably, as compared to the check baits. Results obtained during 
the same period indicate also that a bait consisting of 1 pound of air-— 
dried flies and 1 gallon of a 1 percent solution of sodium sulphide is 
Superior to a bait containing Rk pounds of fresh meat and 1 gallon of 
water for short periods of exposure." 
Derris tract eliminates goat lice.-—-According to 
0. G. Babcock, Sonora, Tex., "A lousy goat that was treated with a der— 
ris-pyrethrum extract mixture, 1 part to 400 parts of water, is free from 
goat lice after a period of observation covering 116 days. The same 
results have held good in another test using a dilution of 1 part to 
S00 parts water." 
Toxicity of rotenone and pyrethrum to Culex mosquitoes .—-Reporting 
on a series of toxicity tests with larvae of Culex sp., W. V. King, 
Orlando, Fla., says, "With an acetone solution of rotenone, complete 
killing within 24 hours was obtained at dilutions up to 1 to 4,000,000. 

