126 BULLETIN 1476, U. S. DEPARTMENT OF AGRICULTURE 
enough, in nearly the exact spot on which the infested cocklebur had 
been found the preceding year. This island is situated about a mile 
from the nearest mainland, so that this cornstalk may have been 
carried by the water for this short distance or for a much greater 
distance, it being impossible to determine the exact spot of its origin. 
This case, however, is very suggestive when the infestation in New 
England is studied and if is seen how closely the oldest and most 
important infestation of this insect follows the shore line. 
The Flight Habits of Moths 
The adults of this insect are strong flyers, active at night and 
resting during the day on the underside of leaves of plants or in other 
sheltered places. They are not easily dislodged by winds, being able 
to cling tightly to the leaves that offer them protection. Experiments 
at the seashore have shown that they are unable to make headway 
against a wind of from 20 to 30 miles an hour, although contesting 
the force of the wind as best they can. 
So little is known concerning the cause of natural migration of 
night-flying insects that it is impossible to say whether this phenome- 
non has entered into the problem under discussion. However, a 
natural migration of adults might be more probable in areas of 
dense population of the insect than in areas only moderately infested. 
Habits of Larvae in Regard to Water 
In order to prove that distribution of the larvae of this insect is 
possible by means of water drift, it is necessary to know that larvae 
are able to survive after cornstalks have floated in water for a con- 
siderable period. In winter and early spring, when the larvae are 
in a dormant condition, it is known that they survive after stalks 
have floated for a few weeks or have even been submerged. In fact 
larvae in experiments have been known to pupate in floating corn- 
stalks. Table 41 gives some results of the survival of larvae in in- 
fested cornstalks that remained in water for protracted periods during 
the winter of 1921-22. In this case the stalks floated until the 
surface of the water was frozen, holding them in ice for some time, 
and in the spring they were submerged after the ice melted. 
Table 41. — Survival of larvce of Pijrausta nubilalix in corn-stalk* placed in water 
Date placed in water 
Kind of water 
Date of re- 
covery 
Total 
number 
of larvae 
Number 
that sur- 
vived 
t 
Dec. 3, 1921 
Salt 
Apr. 10,1922 
Mar. 4, 1922 
Mar. 21.1922 
Apr. 10,1922 
Feb. 14,1922 
150 
146 
141 
122 
90 
1 
17 

10 
1 
Dec. 3, 1921 
Dec. 2, 1921 . . 
do 
Fresh 
Dec. 2, 1921 
Nov. 22, 1921 
do 
.do 
Other experiments of this sort have been conducted with varying 
results, the following being one of the most interesting. 
On February 7, 1921, a number of cornstalks and stubble contain- 
ing overwintering larvae of this insect were placed in a burlap bag, 
weighted down with stones, and thrown into a small brook in Arling- 
