
= (82 un 
says of the latter: "The use of chloropicrin has not increased this 
season, chiefly because of its slow dissipation after. fumigation. The 
California Peach and Fig Growers Association used the gas on figs stored 
in the basement of their Fresno plant. The fumigation began on a Satur- 
day, but workers were unable to enter the storage until the following 
Thursday." 

TOXICOLOGY AND PHYSIOLOGY OF INSECTS 
From F. L. Campbell and W. N. Sullivan, of the Takoma Park, Md., 
laboratory, we have the following note on toxicity of rotenone to house 
flies: "Maggots immersed in a suspension of rotenone for ten minutes 
were not affected. In a recent paper on the pharmacology of rotenone, 
Haag observed that blow-fly maggots completed their development normally 
in meat sprinkled with rotenone crystals. It is very strange that rotenone 
is so very effective against some insects and so ineffective against 
others." 
J. W. Bulger and Abby Holdridge, Takoma Park, who previously re— 
corded the median lethal dose "of acid lead arsenate for the last in- 
star of the catalpa sphinx caterpillar as lying between 0.05 and 0.07 
milligrams per gram and that for the fourth-—instar silkworm as lying 
between 0.08 and 0.09 milligrams per gram," have made comparative tests 
on the relative susceptibility of the sphinx and the silkworm to a non-— 
arsenical stomach poison. They found that "the median lethal dose 
* * * for the catalpa sphinx caterpillar" of the same sample of copper 
cyanide thatF. L. Campbell had tested three years before against the 
Silkworm "lies between 0.02 and 0.03 milligram per gram. For the silk- 
worm * * * the median lethal dose lies between 0.035 and 0.04 milligram 
per gram. These results show that the relative susceptibility of the 
two species for acid lead arsenate and copper cyanide is about the same. 
Thus we have some data to show that the relative toxicity of a series of 
stomach poisons determined for a standard test insect, such as the silk- 
worm, may be the same for related species. But much more work must be 
done before a generalization can be made." 
M. C. Swingle, who is making experiments on insect nutrition at 
Takoma Park, submits the following note on the mortality of American 
cockroaches in cages: "About 150 cockroaches (Periplaneta ameriana L.) 
were collected on nightly visits to a * * * meat—packing concern. Out 
of this number there were about 50 female cockroaches which were held 
for oviposition. Forty of these were placed in pint fruit jars with 
the glass lid placed loosely on the top. The remaining ten were placed 
in specially constructed cages made of celluloid, wire screen, and wood. 
The roaches were fed oatmeal, lettuce leaves, and meat scraps, with a 
plug of moist cotton for water. To date one hundred egg cases (approx- 
imately 2,000 eggs) have been obtained from the females collected. Of 
the forty roaches kept in jars, seven are still alive, while not a 
