DISPERSION OF GIPSY-MOTH LARV2E BY THE WIND. 
13 
receive the full force of the northwest, west, and southwest winds 
directly from the mainland. This island is composed mostly of bare 
rock, with small patches of soil. There is little favorable vegetation 
for gipsy-moth larvae, and .three careful examinations made in the 
spring of 1914 revealed no egg clusters. 
Four hundred and fifty square feet of wire screen was used, and 
an extra screen was made of cotton cloth tacked to a frame 40 feet 
long and 3 feet wide, and tanglefoot applied. It was anchored at 
an incline on the rocks, facing the west. 
On this island there is one cottage which afforded quarters for 
Mr. Harry L. Blaisdell, who was in constant attendance at the 
screen (PI. IV, fig. 1). Arrangements were also made with the 
United States Life-Saving Service for transportation to and from the 
islands on their regular trips to Portsmouth, N. H. Mr. Blaisdell 
recorded the weather conditions hourly from 8 a. m. to 5 p. m., using 
a compass, thermometer, and hand anemometer. He also examined 
the screens continuously and made careful notes on the time and 
wind conditions when each caterpillar was caught, which made it 
possible to determine the source from which it came. Practically 
all the larvae found on the screens were alive, and in most cases they 
were removed very soon after entanglement. 
Table V. — Number of caterpillars caught at Lunging Island, Isles of Shoals, N. H., in 
1914, with direction and distance from which they came. 
Date. 
Other islands 
of the Isles 
of Shoals, E., 
NE., SE., 
and S.,J and 
jf mile. 
Kittery, Me., 
N¥, 7 miles. 
Wallis Sands 
and Rye, 
N. JL, 
WNW., 6 
miles. 
Rye Ledge 
and Little 
Boars Head, 
N. H., W., 
7 miles. 
Seabrook, 
New Hamp- 
shire, and 
Massachu- 
setts line, 
WSW.,11 
miles. 
Plum Island 
(north end), 
Mass., SW., 
13 J miles. 
1914. 
May 20 
6 
6 
1 
1 
May 21 
Mav 22 
May 23 
8 
20 
3 
May 24 
1 
May 2.3 
2 
1 
1 
1 
9 
May 26 
May 31 
June 1 
June 2 
Total 
25 
1 
28 
3 
1 
9 
Sixty-seven larvae were removed from the screen and cotton cloth 
between May 20 and June 2. The wind data given in the table were 
taken on ithe island, but comparison was also made with the records 
taken at Plum Island, Mass., 13^ miles to the southwest. It was 
thought that the air currents on the shore of the mainland where 
most of the small larvae were picked up would be much changed from 
their course before reaching the islands, but only slight differences 
were noted by the two observers during the period. 
