BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 103 
other greenhouse pests. Rose, carnation, snapdragon, cyclamen, fern, 
and other greenhouse plants have been fumigated safely. In winter, 
dosages of 1 to 1V4 pounds per 1,000 cubic feet were effective in over- 
night exposures. The dosage can be reduced by one-half pound in 
the summer at temperatures around 70° F. A combination of nicotine 
and naphthalene showed promise as a fumigant for the greenhouse 
whitefly. 
Investigations were continued on fumigation of vetch seed for the 
vetch bruchid, and schedules were developed for fumigation with 
chloropicrin and methyl bromide. A method of fumigation against 
the European corn borer was also worked out which makes possible 
simultaneous fumigation against this insect and the Japanese beetle on 
crops susceptible to infestation by both insects. 
PHYSIOLOGY OF INSECTS 
In the field of physiology of insects and the effects of poisons on 
the physiological processes, the studies of glycogen in southern army- 
worm blood cells and the effects of a number of poisons on the blood 
cells were completed. Administration of arsenicals or fluorides was 
followed by abnormal degenerative changes in the blood cells, whereas 
administration of rotenone, pvrethrum, phenothiazine, nicotine ben- 
tonite. nicotine peat, and nicotine did not cause marked changes in the 
cells. Among the cellular changes caused by the arsenicals and flu- 
orides were glycogen decrease, change of form, agglutination, vacuoli- 
zation, nuclear deformation, plastid formation, and loss of nucleus. 
It was also found that the buffer capacity of southern armyworm 
blood is great enough to maintain the blood at its normal pH value 
of about 6.6 in larvae subjected for 24 hours to air saturated with 
nicotine. 
The role played by the blood cells and nephrocytes of the cockroach 
in maintaining the insect's resistance to poisoning by sodium arsenite 
and nicotine was investigated. The results indicate that functional 
blockage of the blood cells with Chinese ink caused a decrease in the 
resistance of the roach to nicotine and, particularly, to sodium 
arsenite. 
APPLICATION OF INSECTICIDES 
Investigations to develop more effective methods of applying insecti- 
cides, particularly from the upper air, were continued. In cooperation 
with the Connecticut Agricultural Experiment Station, 461 acres of 
woodland infested with the gypsy moth were treated with air-blended 
lead arsenate and fish oil distributed by an autogiro at the rate of 30 
pounds per acre. The acreage covered was in hilly, heavily forested 
terrain and comprised the largest area of this nature yet treated for 
the gypsy moth by means of rotating-wing aircraft. The operations 
demonstrated the practicability of treating woodland in this manner 
and disclosed the possibility of replacing several ground spray units 
with one aircraft. Available figures indicate that utilization of air- 
craft in such a replacement could reduce by one-half or more the 
cost of spraying similar or rougher areas. While final observations 
concerning the effect of the treatment on the gypsy moth are not yet 
available, preliminary results appear to be excellent. Since in simi- 
lar work conducted during 1939 a dosage of 20 pounds of lead arsenate 
per acre gave 92-percent control, and a 40-pound dosage resulted in 
