iF ia 
These records indicate a very substantial reduction of grub pop- 
ulation in the area covered. 
Stomach poisons in soil.--Tests by W. E. Fleming, F. E. Baker, 
and L. Koblitsky, Moorestown, have been continued with third-instar 
larvae, using material as stomach poisons under controlled conditions. 
Thus far, the tests with C. P. rotenone, and with derris containing 
4 percent rotenone, have indicated that these materials are of little 
value, even when used at the rate of 2,000 pounds per acre. 
PWA and CWA Building Projects 
Public Works allotments.--Public Works funds were allotted to the 
Moorestown, N. J., laboratory for four projects, providing for rebuild- 
ing storage sheds, rebuilding the insectary, rebuilding existing green- 
houses, and building two additional greenhouses, and for general re- 
pairs, painting, and rendering fireprovf the Government-owned laborator- 
ies and storage buildings. This work was completed in March. Rebuilt 
structures included 6 sturage shed with a ground size of 42 by134 feet; 
combined insectary and workrooms, ground size of 30 by 54 feet, with 
small rebuilt greenhouse attached; two new greenncuses, each 21 feet 
4 inches by 51 feet, with attached combined headhcuse and potting shed, 
size 16 by 72 feet, and two existing greenhouses rebuilt into one house, 
size 16 by 51 fect. In addition, all of the other laboratories and 
storage sheds were covered on the outside with sheet metal and were re- 
painted and repaired. 

Civil Works allotment.--Civil Works funds were allotted to the 
Moorestown, N. J., laboratory to provide for remudeling and rebuilding 
the general parasite laboratory. This project has nuw been completed. 
Much of the interior cf the building was torn out and rebuilt and a 
cellar was excavated under the entire structure. This cellar, which 
is 28 by €1 feet, contains six temperaturo—controlled ro.ms, each 7 by 
10 by 7 feet. These rooms are standardly insulated with 4 inches of 
pressed cork on all sides, over which is a layer of #-inch waterproof 
cement plaster. Standard refrigeration doors furnish entrance to 
each chamber. Three of the rooms are equipped with sufficient refriger- 
ation elements to permit their being set individually and retained 
automatically tc run at temperatures from 40° to 60° F. The three 
chambers of the second set have less cooling capacity, so that by the 
introduction of automatically controlled heating elements they may be 
run individually at 60° F. or at any desired temperature above this 
point. The refrigeration unit for the chambers is a York, 2-ton, 
direct expansion "Freon" compressor, which.is a closed system similar 
in principle tv refrigeraticn units used in electric refrigerators... 
"Freon", or "F-12" (trade names for dichlorodifluuromethane), seems 
to be an ideal refrigerant for such collars, for in case of any leakage 
the gas generated is nontoxic and nonexplosive. Provisi:n for humidity 
in each of the chambers consists of an atwmizer which throws a fine 
cloud of nist directly into the air. The atomizer is electrically con- 
trullea by an automatic hydrastat. 
