ae 
plate-froster the infesting larvae are killed within four hours. Sweet 
corn so processed is stored at -—-20° F. until shipped and this treatment 
precludes the possibility of transportation of living material to uninfest— 
ed territory. This 'quick freeze' method was found to be the most rapid 
refrigeration process and further usefulness is indicated if, for the same 
purpose, it is applied to infested products other than corn, such as lima 
beans. The 'sharp process' employed at —-20° F., cold room, was found to 
be effective during an 18-hour exposure in killing all infesting larvae. 
The 'slow freeze' method of refrigeration employing cold—room temperatures 
of zero and 50°F. was found to require an extended pericd of exposure in 
order to be effective. The minimum safe exposure when the top of the stand— 
ard bushel pack is ventilated was found to be 8 days following the time 
at which the center of the pack reaches zero. A-total exposure of 14 days 
to 30° F. killed only 33.3 per cent of the infesting population." 
INSECTS AFFECTING MAN AND ANIMALS 
In the September Monthly Letter a report by 0. G. Babcock, Sonora, 
Tex., On the control of goat lice was given. Mr. Babcock now says: "The 
goats that were dipped at Menard, Tex., on June 16 and 27 are still ap- 
parently free of lice. This comprises an approximate total of over 2,000 
goats on five ranches." 
Mr. Babcock reports results of experiments in trapping blowflies 
with various baits. He says: "The two most interesting baits in the 
blowfly bait tests were the dipyridyl oil and the nicotine. The dipyridyl 
Oil added to the liver started out with a high acidity, and did not catch 
very well at first, but after the 14th day it began to catch guite well. 
The same was true for the nicotine-—liver bait. The pH value for the nico— 
tine~liver bait runs just a little higher than for the dipyridyl oil-liver 
bait. These pH tests indicate rather strongly that the pH values are of 
little value in fly—bait work, but that other factors are of greater im-— 
portance. Other tests need to be run with varying amounts of nicotine and 
dipyridyl oil added to the bait to determine relative efficiency. All 
things considered, the dipyridyl oil has the most promise of anything yet 
used in aiding the ranchmen by developing a bait that will continue to 
catch over a long period of time with the least expense and at the same 
time be the least objectionable bait to handle and care for, the least 
repulsive." 
D. C. Parman, Coachella, Calif., submits a table which gives the 
parasitism of blowflies by Brachymeria fonscolombei Duf. and Mormoni-— 
ella vitripennis Walk. at Uvalde, Tex., for the past three years. H3 
says: "It is noticeable that the average infestation of B. fonscolombei 
for 1929 was 39.55 per cent; it fell to 28.42 per cent in 1930, and rose 
to 56.08 per cent this year; as yet not explained. 
