12 BULLETIN 273, U. S. DEPARTMENT OF AGEICULTUBE. 
Table IV. — Dates and numbers of newly hatched caterpillars caught on screen, with tem- 
peratures, direction of wind, and velocity of wind at Plum Island, Mass., in 1914. 
Date and time removed. 
Number of 
caterpillars 
caught. 
Maximum 
tempera- 
ture. 
Minimum 
tempera- 
ture. 
Average between 9 a. m. 
and 5 p. m. 
Prevailing Wind veloc- 
wind direc- J ity, in miles 
tion. per hour. 
May 20, a. m. and p. m 
May 21, a. m 
May 22, a. m 
May 23, a. m. and p. m 
May 24, a. m. and p. m 
May 25, a. m. and p. m 
May 26, p. m. 
May 27, p. m 
May 28, p. m 
Total 
W. and N¥ 
XE. to SE. 
E. and SE. 
W 
w 
STY 
SW. and TV 
TV. to S 
NW 
A total of 42 caterpillars were removed from this trap between 
May 20 and May 28 — a very short season in comparison to the 
records at Salisbury Beach in 1913. Five of these larvas were 
blown on the screen by winds from the east and south, while the 
remaining 37 came with the winds from the west. Larvae were 
caught during the morning of May 20, when the velocity of the wind 
for that period ranged from 2 to 4 miles per hour, and on the follow- 
ing day, when the temperature ranged from 53° to 60° F. 
SCREEN EXPERIMENT ON ISLES OF SHOALS, N. H. 
The Isles of Shoals (PI. II), located 6 miles off the coast of New 
Hampshire and Maine, was selected as an ideal place in which to 
establish a trap for tests in long-distance spread. An elevated spot 
on Appledore Island was chosen and a screen erected in April, 1913. 
It was not known at that time that Appledore, comprising about 
100 acres, was infested, but subsequent scouting in the summer 
showed that this was the case. This island contains a varied growth 
of low shrubbery, some of which is very favorable food for gipsy- 
moth larvae, but the infestations were slight and covered small areas 
well scattered over the territory. 
The screen was examined at intervals during that year from 
May 1 to June 3 and 14 first-stage larva? were removed during that 
period. Some of these larvae were alive on removal and were taken 
on days when the wind blew directly from the mainland, which 
indicated that many of them came from that source, but there was 
room for question because the island on which the screen was located 
in 1913 was later found infested. 
To eliminate any possibility of error in drawing conclusions another 
island in this group, namely, Lunging, was selected for the experi- 
ment in 1914. It is the most western of the isles and located so as to 
