June 4, 1917 
The Pink Bollworm 
357 
pink bollworm may keep alive and be capable of eventual maturity even 
longer than this. 1 This ability of the larva to sustain life within the 
seed for a prolonged period has an important bearing on the spread of 
the species, as the larvae may be transported any distance with the seed 
and may transform successfully and produce imagoes capable of repro¬ 
duction whenever conditions become favorable. 
This possible suspension of the larval life renders of uncertain value 
any storing of the seed as a safeguard against infestation from such seed. 2 
The instinct of the larva to provide a safe exit to the outer world for the 
moth in the field by gnawing a hole through the husk of the boll, pre¬ 
liminary to the spinning of its cocoon, governs the larva also under 
artificial conditions. If an infested boll is wrapped in tissue paper or in 
cloth, the larva will bite its exit hole through these additional layers, 
spinning its cocoon within the hole. Also, if a mature larva is confined 
in a small pill box or in a capsule, it will tunnel a hole through to the 
outer world and then, conditions being otherwise suitable, will spin its 
cocoon within the hole. When green infested bolls are inclosed in a sack, 
such larvae as are ready to pupate will leave the bolls and eat their way out 
through the sack to find suitable places outside for their cocoons. Even 
a heavy canvas or khaki bag is no barrier. If the larva matures within 
a bale of dry cotton and is sufficiently near the surface of the bale to be 
able to work through the packed cotton, it will do so and cut its way 
through the covering of the bale. Such a larva will riot 'normally make 
its cocoon within the hole in the sack or in the covering of the bale, but 
will seek a suitable place outside because of its instinct to find a firm 
support for the issuing moth. 
This tendency in the larva to seek free access to the outer world for the 
issuing imago has an important bearing on the precautions necessary to 
insure against the introduction of the pest into the United States with 
imported baled cotton. It renders absolutely valueless as a preventive 
any burlap covering of the bales. Such covering will in no degree lessen 
the possibility of importation, as any larva which inay be in the bale and 
which is able to come to the surface can easily cut through the covering, 
and will invariably do so. Such larvae as are within seeds deeper in the 
bale will remain quiescent until the bale is opened and the pressure 
relieved, when they will issue quickly from the seeds and complete their 
transformation. 
1 Gough (36) found larvae hibernating over two years in Egypt. 
2 This applies particularly to seeds stored under usual conditions in a temperate climate—that is. within 
the bolls and in cool dark rooms unsuitable for the issuing of the imago. In the warm climate of Hono¬ 
lulu, however, it was found that loosely stored cotton seeds in open bins would be entirely free of larvae 
in the course of a few months, contrary to the results obtained with baled cotton. 
Vosseler (7, p. 407) also records an experiment with infested seeds placed on a sheet in the sun in which 
all the larvae left the seeds in a few hours. 
