a le 
Ione P. Bassett, of the Orlando laboratory, has completed a report 
on the quantitative determination of soluble arsenic in various sprays 
and the arsenical residue on the foliage. 
Dr. F. Stickney, of the Whittier, Calif., laboratory, has con- 
ducted experiments on heat treatment of date offshoots. The treated 
offshoots have been planted at different places, some being obtained by 
the Citrus Experiment Station at Riverside, Calif. 
C. H. Martin, of the Whittier laboratory, has completed a report 
On the citrophilus mealybug. The insects have been reared at different 
temperatures to determine temperature effects, and at constant tempera— 
tures as compared with fluctuating temperatures. The higher constant 
temperatures reduced size and fecundity in the mealybug. Mr. Martin spent 
a week in Santa Cruz, Calif., closing out the bulb plot held there for 
some time. 
Dr. F. R. Cole, of the Whittier laboratory, is preparing a series 
of sectional maps of southern California, plotting citrus plantings and 
red scale infestations to show resistant areas. Commissioner Ryan has 
been cooperating in Los Angeles Ccunty. Dr. Cole has completed his 
monograph'on the Diptera of the West Coast, a comprehensive study of these 
insects comprising a manuscript of more than 1,000 pages. He has also 
prepared a manuscript on the ortalid genus Euxesta. 
Dr. C. I. Bliss and L. Baird, of the Whittier laboratory, have sub- 
mitted a report on physiological studies on citrus leaves in relation 
to fumigation. They find that the stomata give an early and sensitive 
index to the effect of hydrocyanic acid in fumigation. 
H. R. Yust, of the Whittier laboratory, is studying, for compara— 
tive purposes, the biology of resistant and nonresistant scale stocks 
under the same artificial temperature. So far, no changes in development 
have been noted. 
E. A. McGregor, stationed at Lindsay, Calif., reports that the 
unexpected rain in June washed off most of the sulphur on citrus trees, 
thus affecting thrips control, but owing to the severity of the storm 
the thrips population dropped about 45 per cent. Mr. McGregor reports 
that citrus dusting gives a control of nearly 100 per cent of the citrus 
gray scale. 
Dr. H. H. Richardson, of the greenhouse-insect laboratory, Washing-— 
ton, D. C., found pyrethrins with dilute soap solution effective against 
the greenhouse thrips and against the chrysanthemum aphid. In a long 
series of greenhouse plants tested concentrations up to 20 per cent 
pyridine did not injure any species. Toxicity and plant tolerance studies 
were also made with sulfonated oxidized petroleum oil, which proved satis— 
factory for aphids, but unsuitable for the other insects studied. 
