352 



Eelation" of Water to the Behavior of 



In the latter test, however, the insects were first induced to hibernate in 

 cages in the vivarium, and were then immediately sifted out of the soil, to be 

 finally buried in Plots A and B. The following methods were used in this test : 

 During the period of August 13 to 20, emerging adults to the number of 1,613 

 ( Tucson A, g. I ) were collected and placed in pedigree cages under adverse con- 

 ditions within the vivarium. These conditions were produced by having their 

 food reduced to sliced potato tubers and by adding just enough water to keep 

 the soil slightly moist, so that the beetles were partially desiccated. A census 

 taken September 10 showed that 1,209 insects had successfully hibernated in 



Table 4. — Census of counts on covered plot and open plot. 



these cages, and from this result, it was discovered that their vitality was greatly 

 diminished, for 67 per cent of them were killed by these conditions. Of the 

 survivors, 400 were divided into 8 groups of 50 individuals each, which were 

 placed in tubes buried beside the 8 which were described in the former test. All 

 were left unmolested during the winter and until May 1, when 4 tubes from 

 each plot were examined. Tubes from the covered plot showed that those in 

 sand contained no life ; 2 from adobe contained 54 living beetles ; while 4 were 

 alive in the sand from the covered plot; the adobe portion of this harbored 46 

 living insects. On October 1 the remaining 4 tubes were also examined ; those 

 in adobe soil under shelter contained 12 living beetles, but all were dead in the 

 sand and there were no living animals in either part of the open plot. These 

 experiments proved that beetles of the summer generation, which normally 



