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adults were at least 100 days old. It is interesting to note that this 
species still persists in the vicinity of Wahkeena Falls. This is only one 
of several locations where the species has been breeding in large numbers, 
but it seems to be the only location where A. vexans can be found so late 
in the season. This may be explained by the nature of the geological forma- 
tion about Wahkeena Falls. Breeding takes place along a narrow willow flat 
which is bounded on one side by the Columbia River and on the other by high 
cliffs, which together probably serve as effective natural barriers against 
dispersion. Our records of 1930 show that female A. vexans were taken at 
least 112 days after emergence." 
An investigation of the mosquitoes of Klamath County, Oreg., carried 
on during the summer by M. F. Canova, of Portland, Oreg., has been com-— 
pleted. Mr. Canova's report says in part: "Seven species of mosquitoes 
were found inhabiting Klamath County, Oreg.: * * * Aedes dorsalis Meig., 
eee ee ee 
ape es ek or ne — 
Thom. The members of the genus Aedes were found to be the most numerous 
* * * Aedes dorsalis was the predominant species during the latter part 
of spring and the first part of the summer. Aedes melanimon was the pre— 
dominant species during the latter part of summer. Next in order of abun~ 
dance throughout the mosquito-breeding season came Culex tarsalis, Culi- 
cella inornata, and Anopheles maculipennis. Culicetla incidens were nu- 
merous in various isolated places toward the latter part of August and 
more anophelines were found on the wing then than earlier in the year. *** 
Of major economic importance throughout the season were * * * A. dorsalis 
and A. melanimon. Aedes dorsalis was the predominant species during the 
first half of the mosquito season, and Aedes melanimon * * * during the 
last half of the season. These two mosquitoes pass through their larval, 
or "wiggler," stage in the temporary water of the flooded fields of the 
Klamath region. They develop very rapidly in the rich, warm, hay—infusion- 
ed water, in the direct rays of the intense summer sun. Larvae have been 
known to pupate and emerge as adult mosquitoes in as short a time as seven 
days after their eggs had hatched." 
STORED PRODUCT INSECTS 
Perez Simmons, Fresno, Calif., reports: "Tests of the effective— 
ness of ethylene oxide under covers of water-proofed canvas were made Sep-— 
tember 5 and 8 in a fig storage warehouse. * * * The figs were piled in 
Dulk within walls of open boxes of figs. The piles measured about 25 by 
15 by 5 feet high, and were covered crosswise with three 20 by 30 foot 
pieces of canvas, one at either end and one in the center, overlapping the 
end pieces. A fourth canvass was spread over the whole, lengthwise. The 
dosage rate was 3 pounds of the fumigant to 1,000 cubic feet. Two large 
pans were placed on each pile to receive the fumigant. Provision for weigh- 
ing down the edges of the canvas covering was not made, owing to lack of 
sufficient space between the piles of fruit. In the first test the ethylene 
oxide was allowed to run from a previously cooled cylinder into a bucket con- 
i ee ee ee a ee 
