Dec, 1915] Harris: The Beetle Bruchus. 243 



tions may be taken up in detail later they need not be outlined here. 

 I shall consider: 



(a) The relationship between the number of ovules per pod and 

 the relative number of seeds parasitized by the beetles. 



(b) The relationship between the number of seeds matured per 

 pod and the number infested by beetles. 



(c) The relationship between the position of the seed in the pod 

 and the incidence of the insects. 



Materials and Methods. 



Unsystematized records of the incidence of the beetles are fur- 

 nished after a sufificient lapse of time by the seeds themselves. 



It would of course be most convenient if the pods could be pre- 

 served unopened and all the records made at one time after the 

 emergence from the seeds of all the insects. There is, however, no 

 reason to assume a priori that the insects will develop normally and 

 emerge in full numbers in seeds remaining in the pods. Experi- 

 mentally there is some evidence against such an assumption. Hence 

 the seeds must be removed from the pods and be preserved individ- 

 ually with records of any of the pod characters which are to be 

 considered. 



Materials which seem to be free from pertinent objections are 

 furnished by two lots each of several thousands of pods from my 

 experimental cultures. One of these is a series of Golden Wax beans 

 grown at Lawrence, Kansas, in 1906. The other is a culture of Bur- 

 pee's Stringless made in the Missouri Botanical Garden in 1907.^ 



The pods of these were shelled in the fall or early winter after 

 they were harvested. Each seed was labelled individually with a 

 record of the characteristics of the pod from which it was taken. 

 Such seeds as showed the presence of weevils were so designated. 

 After some months the seeds were gone through again and other 

 supplementary records of the occurrence of beetles were made. 



The tabulation of the characteristics of the pods from which these 

 seeds come in comparison with these of the whole series of seeds 

 produced gives the information sought. 



1 Those who desire may obtain further information concerning the char- 

 acteristics of these plants in other papers by the writer in which they are 

 referred to by the key letters LL and GG. 



