249 



Dec, igis-] Harris: The Beetle Bruchus. 



TABLE III. 

 Infested Seeds in Golden Wax Beans. 



TABLE IV. 

 Infested Seeds in Burpee's Stringless Beans. 



decrease in pods with 7 and 8 seeds. Here, however, the number of 

 seeds available is small as compared with the other pod classes; as 

 the graphs show, these aberrant percentages fall within the limits of 

 twice the standard deviation from the general percentages, and hence 

 cannot be given too much weight. 



The facts presented in the preceding paragraphs show beyond 

 reasonable doubt that the incidence of the so-called bean weevil is 

 not purely random, but that it is to some extent determined by the 

 character of the pods in which the seeds are borne. In pods with 

 larger numbers of ovules and in those with larger numbers of seeds 

 the percentage frequency of infested seeds is higher. One might ex- 

 pect that if one and one only of the two characters of the pod here 

 considered, i. e., number of ovules and number of seeds, were the 

 determining factor in the differential parasitization of the seeds there 

 would nevertheless be some relationship between the other pod char- 



