252 Journal New York Entomological Society. [Vol. xxiii, 



gested that the factor most Hkely to influence the distribution of the 

 weevils among the seeds would be their position in the pods. 



The data have been tabulated to test this point, but I can find no 

 trustworthy evidence of any such relationship. 



Recapitulation and Discussion of Results. 



The purpose of the foregoing paragraphs is the presentation of 

 certain matters of fact concerning the relationship between the char- 

 acteristics of the pod of the common bean, Phaseolus vulgaris, and 

 the relative frequency of parasitization by the so-called bean weevil, 

 Bruchus. 



The results of the examination of the extensive series of data 

 representing two quite dissimilar horticultural varieties comprising 

 6,233 and 8,018 pods producing 18,575 and 21,213 seeds respectively 

 show that the chance of occurrence of a weevil or of weevils in a 

 seed is to some degree dependent upon the number of ovules laid 

 down and upon the number of seeds developing in these pods. 



In pods with larger numbers of ovules the relative number of the 

 seeds which are weevil infested is greater. 



Percentage of parasitization also increases as the number of seeds 

 matured per pod becomes larger. 



Since number of seeds matured and number of ovules formed per 

 pod are positively correlated^ i. e., since pods with larger numbers of 

 ovules produce on the average larger numbers of seeds, a relationship 

 between either of these characters and the incidence of weevils 

 would necessarily result in some relationship between the other char- 

 acter and frequency of parasitization, even though there were no 

 direct causal relationship between them. 



It is diflicult to differentiate and to measure the independent influ- 

 ence of these two characters upon the incidence of the insects. 



Apparently the number of seeds matured has some influence inde- 

 pendent of that of the number of ovules per pod with which it is 

 correlated. Since this relationship seems to be slight, it is probable 

 that the number of ovules laid down is the primary factor. 



The most reasonable hypothesis in explanation of the observed 

 relationships would seem to be that in the young pod size is corre- 



1 Harris, J. Arthur, Arch. f. Entwicklungsmech. d. Organism., 35: 500- 

 522, 1912. 



