-3- 
"These rearings were made in a heated room at the laboratory at an 
average temperature of 75° F. All of the parasites were reared on well- 
grown Ephestia elutella larvae. The numbers that developed on one host 
larva ranged from one to nine." 
Early in December A. W. Morrill, ir.. began a series of experi- 
ments at Richmond to gauge the degree of cold necessary to control 
laryae of the tobacco beetle by freezing. He placed well—grown larvae 
in pill boxes having a volume of 2.35 cubic inches and filled with 
pipe tobacco, snuff, or pulverized fine-cured tobacco. It was found 
' that a temperature of -4° C. gave only 10 per cent kill in a 24-hour 
exposure, whereas a temperature of -8° C. resulted in 100 per cent 
kill after the same exposure. 
TOXICOLOGY AND PHYSIOLOGY OF INSECTS 
F. L. Campbell and W. N. Sullivan, Takoma Park, Md., are continu— 
ing their experiments to determine the toxicity of rotenone to house 
flies. Dr. Campbell reports: "Fifteen groups of 50 flies each were 
treated with a l1-to-5,000 solution of rotenone in acetone. * * * Most 
of the flies that were not normal (Moribund) at the end of 24 hours 
after the application of the fog died during the next 24 hours. The 
results may therefore be summarized by giving the average mortality at 
the end of 48 hours, which was 42.9 per cent. The mortality in indi- 
vidual tests ranged from 10 per cent to 70 per cent in 48 hours, a 
sreater variability than would be expected under the uniform methed of 
application of the poison. This variability can probably be reduced 
by selection of flies of the same sex and those that have taken plenty 
of milk on the day of the test. As a check, 50 flies were treated with 
acetone on five occasions. The mortality ranged from 0 to 8 per cent in 
48 hours. The mortality of flies treated with rotenone suspended in 
water at 1—to-5,000 was no greater than that in the checks." 
D. E. Fink, Takoma Park, devoted the month of December to the pro- 
ject, "Metabolic Activity during Hibernation." He says: "The average 
weight of hibernating larvae of Carpocapsa pomonella L. during the 
first half of the month was 44.67 milligrams and during the latter half 
41.75 milligrams, or a loss in weight of 6 per cent. The water content 
remained constant during the month and averaged 59 per cent. The total 
fat content (ether extract) averaged 19 per cent of wet weight. A lar- 
va that weighed 44.92 milligrams ccntained 9.42 milligrams of fat, or 
20 per cent of wet weight. It also contained 0.232 milligram of sugar 
as glucose, or 0.5 per cent, and 0.53 milligram of glycogen by weight, 
or 0.45 milligram determined as glucose, which is equivalent to 1 per 
cent glycogen. Ancylis comptana Froel., on the other hand, averaged in 
weight 12.93 milligrams during the first half of the month, and 10.90 
milligrams during the latter half, or a loss of weight of 15 per cent. 
The water content was 71 per cent during the first half of the month and 
69 per cent during the latter half. A larva that averaged 12.665 mill- 
igrams in weight contained 1.105 milligrams of fat, or 8per cent of wet 
