THE BOLL WEEVIL PROBLEM. LG 
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 
little inclined to fly. There is always a movement from fields in all 
directions in search of hibernating quarters in the fall and a corre- 
sponding movement from such quarters to the cotton fields in the 
spring. Nevertheless, when the insects reach cotton fields in the 
spring there is little further movement until the general dispersion 
begins. Ordinarily between the middle of August and the first of 
September the weevil seems to be seized with an instinct to migrate. 
It was thought at one time that this movement was forced by ex- 
cessive reproduction and took place only when all squares and bolls, 
or the majority of them, became infested. Investigations have shown, 
however, that the dispersion takes place frequently when the fields 
are only slightly infested. In other words, the insect has a well- 
developed instinct for extending its range into new territory. It is 
this instinct that has caused the extension of the infested area in the 
United States year by year. The weevil does not fly in any particular 
direction except as governed by the wind. If there is no wind or only 
a light one, a weevil is as likely to fly in one direction as in another. 
The individuals carrying the infestation into new regions have been 
those that happen to radiate in the direction of previously uninfested 
territory. 
The fact that the weevil moves about but little except at one season 
is of great benefit to the farmer. As the movement referred to does 
not begin until after the time when a crop is normally made, it 
zmounts to little after a region has become infested. On the other 
hand, the limited movement at other times of the year makes it pos- 
sible for any individual farmer to obtain the best results from his 
own efforts in fighting the pest. The danger of his efforts being 
thwarted by the arrival of weevils from fields where no precautions 
have been taken is not so important as it is sometimes considered. In 
fact, it is not important enough to warrant any farmer in deferring 
action on account of the indifference of his neighbors. 
The above statements give only an outline of the life history and 
habits of the boll weevil. More complete information can be ob- 
tained from Bulletin 114 of the Bureau of Entomology, which may 
be obtained for 25 cents upon application to the Superintendent of 
54614°—Bull. 512—12 3 
