14 BULLETIN" 273, IT. S. DEPARTMENT OF AGRICULTURE. 
It will be noted, according to the records taken on Lunging Island, 
that nine larvae came from the southwest, that is, from Plum Island, 
13J miles away. The weather records at the latter place indicate 
that conditions were such that at least . 18 of those caught on the 
screen at Lunging Island came from Plum Island, or more distant 
points in that direction. 
Thirteen and one-half miles is the maximum record for distance 
that larvae have been carried by the wind in all experiments thus far 
conducted by us, yet it is probable that the limit has not been reached. 
The locations for securing such records, together with suitable con- 
ditions with reference to infestations, are rare. 
DISPERSION EXPERIMENTS ON THE HILLS OF NEW HAMPSHIRE IN 1913 
AND 1914. 
In the scouting operations conducted by Mr. L. H. Worthley in the 
outside territorjr infested by the gipsy moth, numerous infestations 
were being found on hilltops. It could not be ascertained whether 
this spread was the result of the wind, vehicles, or other possible car- 
riers — man or animals. These lulls contained woodlands, orchards, 
pastures, mowings, and roads over which there was more or less 
travel, making spread possible artificially. Thinning was practiced 
in these infestations, egg clusters were creosoted, and bands of 
tanglefoot were placed on the trees to keep the first-stage cater- 
pillars hatching near the ground from ascending the trees, thereby 
decreasing their chances of spread by the wind. 
To investigate the source of these hilltop infestations, one hill was 
selected in each of four towns in New Hampshire, namely, Andover, 
Henniker (PI. IV, fig. 2), Hillsboro, and. Troy, and large screens 
erected thereon as traps for the small caterpillars. (See also Plate 
VII.) It seemed desirable to know if these colonies were the result 
of windspread, and whether caterpillars were being carried from hill- 
top to hilltop, valley to hilltop, or vice versa, so that scouting and 
control methods could be changed accordingly. 
The screens were constructed of f-inch mesh poultry wire 3 feet 
wide. This was stapled to posts set in the form of a T. The 
posts were about 12 feet high and guyed with No. 13 wire. The 
wire was fastened in two widths, one above the other, making a 
screen surface 6 feet wide. The top selvage ranged from 10 to 12 
feet from the ground owing to the level of the land. The screens 
were erected with one wing 35 feet long, facing the north and south, 
and another, 40 feet long, facing east and west. The total number 
of square feet exposed to the winds in each screen was 450. 
There were known infestations one-third to two miles in all directions 
from the screens in the foregoing towns, but negative results were 
