CRUSHINCS OF HOLL NVKKVII, HV l'K» iLIFKRATION. 37 



EXI'LANAIION or .MECIIAN'K'AL ACTION. 



A briof oxj^lanation of some additional points n><;ar(linp: the forma- 

 tion of i)rolif('rMtion may serve to show more clearly how it becomes 

 possible for the j)laiU to literally cnisli its irritatin«=j foe. The explana- 

 tion will ])e <jiven for bolls rather than for squares, tli(nio:li the real 

 eil'ect of j^roliferation is the same in squares as in bolls. 



Proliferation usually bejjiiis in the layer of cells adjoining; tlie thin, 

 tou<;h linintz; within each sectioi\ of the boll. By far the i^reater j)art 

 of this formation jjrojects throufjh the rupture made by the weevil in 

 (lie-tou(;h linin*!; and forms a rather hemi.spherical mass protruding 

 from the inner side of the carpel (PI. V, fig. 17) and pressing into the lock. 

 Tile fornuition sometimes, though not always, begins before the hatch- 

 ing of the egg, which may be moved quite a distance, in some cases, by 

 the pressure of the mass behind it. In otlier cases the e^f^i^, becomes 

 enveloped and the larva hatches into tlie j^roliferous mass. In such 

 cases it may be destroyed early in life, though it will often make its 

 way into the lock, eating its way as it goes. As it feeds the larva is 

 continually injuring and irritating tissues capable of proliferati(m, 

 which thus becomes started all around the larva and gradually jm.shes 

 in upim 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 ])y 

 t he masses of cells pushing in ufxm it and the larva can not possibly eat 

 away the forming mass raj)idly enough to preserve room for it.self to 

 nu)ve (PI. V, fig. 20). Though it may be nearly or quite full grown, it 

 can not escape from its narrowing prLson and soon Ijccomes so closely 

 enveloped as to be unable to move in any direction. It is then an easy 

 victim for the relentless pressure of forming cells and is literally crushed 

 to death in its prison (PI. VI, fig. 21). 



Very frequently, indeed, instances are to be found in which the plant 

 gets a tardy vengeance on the pupa or the newly transformed adult 

 (PI. V, fig. 19). Wh(>ther death results wit bin a short time or the victim 

 isallowed toemerge with only .somcdeformity to tell of its narrow escai>e 

 within the boll, depends largely upon the continuance of the prolifcTa- 

 tioTi. Deformed pupa* and adults are by no means uncommon and in 

 nearly all cases they are undoubtedly the j)artial victims of this form of 

 plant defense. Many of these specimens have been so deformed by pres- 

 sure upon the j)ui)a that the adult cannot feed. Th(>se would be unable 

 to make thi'ir escape from the i)oll did it not happen souietimes that the 

 n.»;turing of the boll breaks open the |>rison cell of these victims and 

 turns them out only to perish slowly by starvation. 



