112 BULLETIN 1476, U. S. DEPARTMENT OF AGRICULTURE 
flight of at least three-fourths of a mile. It was believed, however, 
that these experiments did not indicate the real limits of dispersion 
of the moths by flight, keeping in mind their relatively long period 
of life and the distance which they have been observed to fly in single 
flights. In order, therefore, to obtain additional information upon 
this point, a total of 8,650 moths stained with an aqueous solution 
of carbol fuchsin (acid) were liberated from a central point at 
Truro, Mass., on Cape Cod, during August, 1921. This region was 
selected for the experiment on account of the open nature of the 
country and the fact that areas of corn and other favorite host 
plants were few and far between. Although there is no evidence at 
present to indicate that high hills, large bodies of water, or densely 
wooded areas are barriers to the flight of the moths, yet it seemed 
advisable to select a region having as few of these potentially limiting 
factors as possible. The selection of Truro as the point of libera- 
tion was also influenced by the fact that the prevailing winds during 
August are from the southwest, which fact probably would influence 
the flight of the moths toward the open country to the northward, 
between Truro and Provincetown, 9 miles distant. 
Recovery of the stained moths was attempted by systematically 
sweeping all susceptible plants and other vegetation likely to be 
frequented by the moths, in the surrounding country. The territory 
examined included that portion of Cape Cod lying north of Well- 
fleet. From the point of liberation it extended 10 miles northwest 
to the tip of the cape, 2 miles east to the ocean, 5 miles south, and 1 
mile west to the ocean. As previous experiments had resulted in the 
recovery of the moths at a maximum distance of nearly a mile from 
the point of liberation, no examinations were made within this 
limit. 
Table 39 gives the results of this experiment. 
Table 39. 
-Result of experiment in sweeping for stained Pyrausta nuoilalis 
moths on Cape Cod, Mass. 
Maxi- 
mum dis- 
tance of 
exam- 
inations 
from 
point of 
libera- 
tion 
Recoveries 
Direction 
Number ! 
of Sex 
moths 1 
! 
Distance 
from 
point of 
libera- 
tion 
Remarks 
North 
Miles 
3.5 
3.5 
3.5 
10.0 
10.0 
10.0 
10.0 
2.0 
2.0 
5.7 
5.0 
2.3 
1.0 
i 
i 
i 
i 
i 
i 
i 
None. 
None. 
None. 
None. 
None. 
Female 
do.... 
do..„ 
Male 
do.... 
Female 
Male 
Miles 
3.0 
2.4 
2.6 
2.7 
2.8 
4.7 
5.0 
Gravid. Swept territory to ocean 
Do 
beach. 
Not gravid. 
Do 
Gravid. 
Northwest .... .. 
Do 
Do.. 
Do. 
Do 
Swept territory to ocean beach. 
Do. 
East 
Do. 
South 
Do. 
West ! . 
From this table it will be noted that, under the conditions of the 
experiment, moths of both sexes were recovered at a maximum dis- 
tance of about 5 miles from the point of liberation, and that three 
