PINK BOLLWORM OF COTTON IN MEXICO. 21 
season till December and make a complete life cycle every 31 days, 
there are six generations, but if the moths do not emerge from the 
resting larva? until the fall and the first generation goes into the rest- 
ing stage again, the whole year may be passed in only one generation. 
FEEDING HABITS OF LARV^. 
LARV^ FEEDING ON LEAVES AND STEMS. 
The feeding of the pink bollworm on the leaves of cotton is of no 
economic importance. It is a forced condition rather than a voluntary 
one. If the eggs have been deposited a long way from the squares 
or bolls, the larvae may feed slightly on the leaves while searching for 
suitable food. In such cases slight abrasions on the surface of the 
leaf or minute pinholes through the leaf occur. The larvae feeding 
in this manner appear either to die for lack of sufficient nourishment 
or to be destroyed by other insects. No larvae older than those of 
the second instar were ever observed feeding on leaves and only 
two or three cases of the second instar. No indications of entrance 
into the bolls by larvae of the second or later stages were ever 
observed under field conditions, except where the larvae had been 
feeding in blossoms and had worked downward into the newly set 
bolls. Willcocks (7) records larvae feeding in the stems of the 
plants just above the surface of the ground in Egypt, but this class 
of injury was never seen in the Laguna. 
LARVAE FEEDING IN SQUARES AND FLOWERS. 
The young larvae enter the squares by cutting directly through the 
undeveloped flower petals and feed on the pollen and fleshy parts 
of the embryonic flower, usually reaching the third or fourth instar 
by the time the flower opens. These infested flowers do not open 
normally, but have a peculiar rosette appearance which is well shown 
in Plate III, A. The tips of the corolla in infested flowers are 
webbed together by the larvae with fine silken threads which prevent 
their opening wide and exposing the larvae to the attacks of other 
insects and the heat of the sun. 
These infested flowers are easily distinguishable from normal 
flowers in walking through fields of upland or short-staple varieties. 
Even though the percentage of infested flowers was about the same 
in Egyptian or long-staple cotton the pronounced rosette effect was 
never seen. The corolla is longer and larger in Egyptian varieties 
and the threads spun by the larva probably are not sufficiently 
strong to prevent its opening. When infested flowers are examined 
the larva is usually found beneath a fine silky web, covered with 
frass and pollen grains, and feeding upon the anthers. If full-fed when 
the flower opens it may leave it the first day and drop to the ground 
for pupation. This is especially apt to occur if the larva is dis- 
