LARGE-CAGE EXPERIMENTS^, 1900-1. 55 



LARGE-CAGE EXPERIMENTS, DALLAS, CALVERT, AND VICTORIA, 



TEX., 1906-7. 



PLAN OF EXPERIMENTS. 



Profiting by the work done during; former seasons, plans were made 

 by Mr. W. D. Hunter, in charge of the investigations, for much more 

 careful and extensive work during the winter of 1906-7 than had 

 ever been undertaken. Three localities for the experimental work 

 were selected representing in a general way the northern, central, and 

 southern sections of the State. In these localities, also, much work 

 had previously been done and the results for more than one season 

 could therefore be used in a comparative way. At Dallas, Calvert, 

 and Victoria screen-covered cages were erected, each being 20 feet 

 wide, 50 feet long, and about 6^ feet high. (PI. YI, figs. 1, 2, and 3.) 

 These cages were divided into ten sections by partitions, each section 

 having a ground area of 100 square feet. The three localities selected 

 offered a considerable range in geographical and climatic conditions. 

 Each section of the cage was provided with a door/:)pening to the 

 outside through which access could be had to a section without 

 disturbing the conditions in any other section. It was planned to 

 provide similar conditions of shelter in corresponding sections and 

 to confine weevils in corresponding sections at as nearly the same 

 date as might be possible in each of the three sections. The weevils 

 used were collected in the immediate locality where they were placed 

 in hibernation. In this way it was anticipated that data might be 

 obtained bearing especially upon the following points: 



(1) The effect of the time of entrance into hibernation upon the 

 survival of weevils. In the experiments first started it was necessary 

 to force entrance into hibernation, if possible, or starvation by the 

 destruction of the food supply. The geographical range was expected 

 to increase the interval between the beginning of the experiment in 

 each locality and the time when weevils would normally hibernate. 



(2) The effect which the complete destruction of food supply at 

 varying dates might have upon the success of hibernation. For these 

 experiments the shelter conditions were as uniform and as favorable 

 as it was possible to make them in the different localities. It was 

 hoped through these tests to determine the minimum interval which 

 must elapse between the destruction of stalks and the successful 

 hibernation of the weevils. 



(3) To determine the effect of exceptionally favorable and unfavor- 

 able conditions of shelter upon the hibernation of weevils placed in 

 the cages upon the same date. It was intended that the shelter 

 conditions provided should be so exaggerated as to represent the 

 extremes of conditions which might naturally occur in the field. 



