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now turning their attention from the original hosts, which are gen- 
erally not very numerous, to the boll weevil, which offers abundant 
and favorable opportunities for reproduction. They thus ally them- 
selves with the farmer for the protection of the cotton crop. In the 
following pages numerous suggestions will be made regarding the 
means that the farmers may take to increase the effectiveness of the 
work of these parasites in reducing the numbers of the boll weevil. 
Other insect enemies.—In addition to the true parasites described 
above, the boll weevil suffers from a number of insects which are not 
parasites in a strict sense but prey upon it as food. The principal 
ones of these predatory enemies are ants. Of these, 12 species are 
known to attack the weevil. They are the minute brown ants and yel- 
lowish ants that occur frequently in cotton fields and are observed 
running over the plants or on the ground. Their work is not against 
the adult weevils, but against the immature stages in the squares. 
Some species devote their attention principally to the squares that 
have fallen to the ground, while others habitually seek the insects 
within the squares that remain hanging on the plants. The larva of 
the weevil, incased in a thin covering, offers a source of food that the 
ants are not inclined to overlook. They gnaw through the thin shell 
inclosing the weevil larva and the latter is soon destroyed. In some 
cases more than half of the immature stages in fields have been found 
to be destroyed by ants alone. To find 25 per cent so destroyed is not 
a rare occurrence. In this bulletin methods will be pointed out for 
making use of these friends of the farmer and increasing the im- 
portant effect they naturally have in reducing the numbers of weevils. 
Other factors in natural control.—In addition to the principal factors 
in natural control which have been mentioned there are several of 
minor importance. Among these may be mentioned proliferation, 
which sometimes crushes the immature weevils, and determinate 
growth, which may prevent the development of the fall broods of the 
weevil. Attention is also called to the agency of birds in the destruc- 
tion of the boll weevil, which has been given full attention in the 
publications of the Biological Survey of this Department. 
DISSEMINATION. 
The boll weevil moves from place to place by flight. Although it 
is a weak flyer compared with many insects, it has been known to 
cover a distance of more than 40 miles in a very short time. Its 
flight can not be prolonged, but successive short flights, especially in 
connection with favorable winds, often carry the insect to consid- 
erable distances. This is the case, however, only during the so-called 
dispersion period, which extends from about the middle of August 
to the end of the season. During the rest of the year the weevil is 
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