2 BULLETIN 1204, U. S. DEPARTMENT OF AGRICULTURE. 
during the season of 1022. It was evident, however, that in the pre- 
liminary tests, since boll-weevil control is not as immediately obvious 
and easy to measure as that of the leaf-feeding insects, difficulty 
might be anticipated in determining the thoroughness of poison dis- 
tribution. Consequently, it seemed likely that the principal measure 
of success in distribution over the plants which might be obtained 
from purely preliminary experiments, would be plant analyses to 
determine the amount of arsenic present, which is a very unsatis- 
factory expedient at best. 
An opportunity to place the tests on an entirely different basis, 
however, was afforded by the outbreak of the cotton leafworm (Ala- 
bama argillacea Iliibn.) which appeared over several of the Southern 
States. The first generation of this worm became active during 
the latter part of July, in rather unusual numbers, indicating a heavy 
infestation in the next generation, which might be expected about 
three weeks later. This provided an excellent opportunity for testing 
airplanes as a means of distributing poison over the cotton fields by 
making an effort to control the leafworms rather than the weevils. 
Ajrangements were accordingly immediately made with the Air 
Service of the United States Army for detailing planes for these 
lests. Tallulah. La., was selected as a suitable location for the ex- 
periments, since the conditions found there, as regards flying, are 
fairly representative of the more favorable conditions encountered 
in the Cotton Belt. Furthermore, the location of the Delta Labora- 
tory of the United States Bureau of Entomology at that point pro- 
vided exceptional facilities for the construction and other work in- 
volved in the tests. Two planes were detailed to the tests, arriving 
about the 1st of August. These were piloted by Lieuts. G. L. Mc- 
Neil and Charles T. Skow. Lieutenant McNeil remained throughout 
the period of the te^ts. while Lieutenant Skow was replaced after 
about 10 days by Lieut. L. C. Simon. All of these men and the equip- 
ment were provided by the Montgomery Aerial Intennediate Depot 
( now Maxwell Field) of Montgomery, Ala. In addition to the pilots, 
three enlisted men were provided, and the experimental work was 
further assisted for a few days by the presence of a photographic 
plane from the same field, piloted by Lieut. L. P. Arnold, the photo- 
graphic work being done by Lieut. J. M. McDonnell. 
DUST HOPPER CONSTRUCTION. 
The first flights in these tests were made with limited quantities of 
poison, carried in bags in the plane and either dropped over the 
side by hand or emptied out through au opening in the bottom of 
the fuselage. After a few such preliminary flights, it was found ad- 
visable to construct "hoppers" which would carry the poison dust 
and deliver it into the air at a controlled rate. The hopper which 
was used nt Dayton was constructed to hang outside of the fuselage, 
but it seemed decidedly preferable to fit the new hoppers inside so as 
to discharge through the fuselage. The cowling was removed from 
the observer's cockpit of the plane, 8 and the hopper was designed to 
utilize as much of the available space as possible and still leave room 
for a man to ride behind the hopper to operate it. 
'Tin- DlaneB provided for this work were of th<> typo commonly called the '-Curtis H." 
equipped fur training observers, and thus had a rear cockpit, but without dual controls. 
