Oye = 
TOXICOLOGY AND PHYSIOLOGY OF INSECTS 
Derris apparently not entirely dependent on rotenone for insecti- 
cidal effects.—-Summarizing results of tests by himself and W. N. Sullivan 
on the relative effectiveness of rotenone and derris extracts on mosquito 
larvae, F. L. Campbell, Takoma Park, Md., reports: "When suspended in 
water, rotenone was relatively ineffective against fourth-instar mos- 
quito larvae, Culex quinquefasciatus Say, from Florida. It was found 
that the effect of rotenone was greater in aqueous solutions of sodium 
bicarbonate and still greater in aqueous solutions of gelatin. Check 
solutions of these two substances had no effect on the larvae. The 
use of gelatin promises to permit a fairer comparison of the effect of 
rotenone and derris extract against mosquito larvae. Rotenone is not 
sufficiently soluble in kerosene to make an effective spray for house 
flies. However, an effective preparation was made by percolation of 
kerosene through derris powder, indicating that rotenone is not the 
only substance in derris that is toxic to house flies. Effective con— 
centrations of rotenone can be obtained in 10 percent solutions of 
chlorobenzene or cyclohexanone in kerosene." 
FRUIT AND SHADE TREE INSECTS 
Pecan weevil not controlled by soil cultivation.--T. L. Bissell, 
Experiment, Ga., reports the completion of experiments to determine 
whether the larvae of the pecan weevil will burrow into soil that has 
been plowed, raked, and rolled. Results on two types of soil--Cecil 
clay loam and Cecil sandy loam--show that the cultivation performed 
did not prevent larvae from burrowing. These results corroborate those 
obtained in January, that practically the same number of larvae bur-— 
rowed in treated and untreated soils, 
Trap catches of moths at Albany, Ga.--Herbert Spencer reports that 
"Collections of moths at bait traps hung in pecan trees in a commercial 
grove have been continued and, while fewer individuals have been caught 
than in previous months, the same species of cutworms taken previously 
have appeared in numbers during each warm period, This work is being 
done to obtain information on winter hosts that might carry Trichogramma 
minutum Riley through our mild winters by furnishing eggs upon which the 
parasites might subsist." A total of 1,674 moths were caught in Febru- 
ary, while temperatures ranged from 33° to 83° F. 
Heat sterilization of codling moth larvae.—-"Further data were ob— 
tained in February," by E. H. Siegler and Francis Munger, Takoma Park, 
Md., "on the effect of high temperatures against codling moth larvae. 
* * * the heat conductivity of the wood was lower than that of the cor— 
rugated paper. This was to be expected and merely serves to emphasize © 
the fact that the sterilization of larvae in a commercial way will re- 
cuire a considerable exposure to heat in view of the protection afforded 
the larvae by the wood of the lug boxes, baskets, etc. In these pre- 
