eat ye 
horsemint was maturing the flea hoppers were building up a heavy pop-— 
Wlation on crorons From April 19 to May 19 the population on croton 
averaged from 122 to 307 insects per 100 sweeps, but increased to 1,816.5 
per 100 sweeps by May 31. By May 15 considerable migration to cotton 
had occurred and an average of 84.3 adults and nymphs per 100 sweeps 
were taken. Cotton was squaring by this time and considerable damage 
was being caused in certain fields. Migration was also shown by the 
catch on the flight screens; an average of 207 adults per screen during 
May were taken in cotton fields, 43 from screens in ranch country, and 
14 from one screen on the bay front. More flea hoppers were taken on 
the east sides of the screens, facing the prevailing winds, than from 
the other directions." 
INSECTS AFFECTING MAN AND ANIMALS 
Flood stage of river leaves mosquito larvae in moss and rotten 
wood.—-Reporting on life history and habits of Aedes mosquitoes, H. H. 
Stage, Portland, Oreg., says: "In the month (May) several additional 
Samples of moss on trees and bridges, and rotten wood from fallen logs 
were flooded in the laboratory. A few handfuls of moss taken from 
near the base of a concrete railroad bridge produced 17 A. vexans Wane 
vae when flooded. This part of the bridge is flooded when a river 
stage of from 16 feet to 18 feet is reached. The moss was growing on 
the concrete and was not protected by overhanging shelter of any kind. 
A sample containing approximately 1 Square foot of rotten wood surface 
taken from the top of a fallen log produced 1,070 larvae when flooded 
in the laboratory. Of these 96 percent were A. vexans; the rest were 
A. aldrichi. These logs are flooded when a river stage of 16 feet is 
reached," 
Equipment for determination of freezing points of insect tissue.— 
-Wm. Robinson, Washington, D.C., reports: "Our potentiometer and thermo— 
couple set-up has been arranged for use in determining the freezing and 
undercooling points of insect tissues. A freezing chamber was made of 
a l-quart thermos bottle. The low temperature was obtained by cooling 
gasoline with solid carbon dioxide, or ‘dry ice.' The dry ice was made 
in our laboratory from liquid carbon dioxide in a drum. The come 
eaSily collected in a cloth bag placed over the opening of the drum. 
It is much more convenient to get the ice in this way than to purchase 
it in the solid form, is less expensive, and can be had in any quantity 
at any time at a few minutes' notice. A freezing temperature of -—25° C. 
Was obtained and much lower temperatures may be had if necessary." 
Sheep botfly larvae of all stages found in heads of sheep and 
goats.—-0. G. Babcock, Sonora, Tex., reports that "Collections of larvae 
of Oestrus ovis L. are being made nearly every week. All stages are to 
be found in the heads of sheep and goats from first undeveloped first 
instars to mature grubs. Occasionally a dead grown larva is found, 
always associated with more or less mucus of the sinuses, usually the 
