- 12 — 
punctella Hbn., and Ephestia kuehniella Zell., fumigated by being placed 
for 3, 6, and 24 hours, respectively, in a saturated atmosphere obtained 
by use of paradichlorobenzene crystals, resulted in a 100 per cent kill 
with the 6—hour or longer fumigation. The examinations were continued 
both as to the treated eggs and a check lot over a 10-day pericd. Similar 
fumigation of adults of the confused flour beetle (Tribolium confusum 
Duv.) resulted in 100 per cent kill after li-hour exposure, whereas a 
5—-hour exposure wes necessary for 100 per kill of the larvce. A 2-hour 
exposure was sufficient to kill the larvae of Ephestia kuehniella and a 
l-hour exposure to effect a similar kill of adults of the rice weevil 
(Sitophilus oryza L.). 
Paradichlorobenzene inhibits feeding of clothes-moth larvae.—— 
Wallace Colman, Silver Spring, Md., has been testing the effect of paradi- 
chlorobenzene upon the feeding of larvae of the webbing clothes moth 
(Tineola biselliella Hum.) held at a constant temperature of 25°C: 
"There was no feeding in the treated jar and very light webs were formed, 
whereas in the check jar there was heavy feeding and strong webs were 
formed. A series of tests under practical conditions and at normal 
temperatures, in which half the larvae were fumigated continuously and 
the other half only on alternate weeks, shows clearly the lag effect of 
paradichlorobenzene vapor upon the feeding of larvae of the webbing 
clothes moth," 
Mr. Colman also reports an experiment with evaporation of paradi- 
chlorobenzene crystals in a small shellacked closet constructed of wall 
board. After this fumigation the closet was opened and aired for 4 1/2 
hours. In the closet were then placed 10 clothes moths on woolens, and 
the closet was closed, After 30 days 4 larvae were still alive and there 
had been no feeding. At the end of 60 days there were 2 living larvae 
and 1 of these had resumed feeding. Mr. Colman believes that the closet 
had initially received an excess of the paradichlorobenzene over that 
required to saturate the air and that "A large part of the excess must 
have been taken up by the walls, later to be given off as an effective 
fumigant. The test was conducted at room temperature, averaging 75° F: 
When the fumigation period is lengthy or continucus, the absorbed paradi-— 
chlorobenzene would constitute a buffer or reserve supply of fumigant 
to be taken up by the air of the closet when the concentration fell 
below a certain point." 
TOXICOLOGY AND PHYSIOLOGY OF INSECTS 
Loss of toxicity of rotenone in sunlight preventable.--F. L. 
Campbell and W. N. Sullivan, Takoma Park, Md., report on experiments in 
which "Mosquito larvae were used as test insects to determine the ef— 
fect of light on the toxicity of rotenone, dihydrorotenone, rotenone 
hydrochloride, and mixtures of rotenone with bentonite and with lampblack. 
It was found that the toxicity of all the materials just named was more 
Or less reduced by exposure on glass plates to sunlight for 10 and 20 
days and to an arc light for periods equivalent to about 1 and 2 months’ 
