CRUSHING OF BOLL WEEVIL BY PROLIFERATION. 37 
EXPLANATION OF MECHANICAL ACTION. 
_ A brief explanation of some additional points regarding the forma- 
tion of proliferation may serve to show more clearly how it becomes 
possible for the plant to literally crush its irritating foe. The explana- 
tion will be given for bolls rather than for squares, though the real 
effect of proliferation is the same in squares as in bolls. 
_ Proliferation usually begins in the layer of cells adjoining the thin, 
tough lining within each section of the boll. By far the greater part 
of this formation projects through the rupture made by the weevil in 
the tough lining and forms a rather hemispherical mass protruding 
from the inner side of the carpel (PI. V, fig. 17) and pressing into the lock. 
The formation sometimes, though not always, begins before the hatch- 
| ing of the egg, which may be moved quite a distance, in some cases, by 
e pressure of the mass behind it. In other cases the ege becomes 
snveloped and the larva hatches into the proliferous mass. In such 
cases it may be destroyed early in life, though it will often make its 
vay into the lock, eating its way as it goes. As it feeds the larva is 
continually injuring and irritating tissues capable of proliferation, 
which thus becomes started all around the larva and gradually pushes 
in upon it from all directions (PI. V, fig. 18). It may happen in this way 
that the space which the larva has eaten out as it grew becomes filled by 
the masses of cells pushing in upon it and the larva can not possibly eat 
away the forming mass rapidly enough to preserve room for itself to 
move (Pl. V, fig. 20). Though it may be nearly or quite full grown, it 
can not escape from its narrowing prison and soon becomes so closely 
enveloped as to be unable to move in any direction. Itisthen an easy 
ictim for the relentless pressure of forming cells and is literally crushed 
fo death in its prison (PI. VI, fig. 21). 
Very frequently, indeed, instances are to be found in which the plant 
rets a tardy vengeance on the pupa or the newly transformed adult 
Pl. V,fig.19). Whether death results within a short time or the victim 
_Isallowed to emerge with only some deformity to tell of its narrow escape 
rithin the boll, depends largely upon the continuance of the prolifera- 
ion. Deformed pupe and adults are by no means uncommon and in 
early all cases they are undoubtedly the partial victims of this form of 
lant defense. Many of these specimens have been so deformed by pres- 
ure upon the pupa that the adult can not feed. These would be unable 
o make their escape from the boll did it not happen sometimes that the 
laturing of the boll breaks open the prison cell of these victims and 
ums them out only to perish slowly by starvation, 
