360 



Eelation of Water to the Behavioe of 



The evaporation rates here shown gave greater differences within this experi- 

 mental cage than were obtained by Fuller (1911) for all the plant associations 

 studied. Shelf ord (1913) uses Fuller's data with tables and compares them 

 with conditions in certain animals, stating that distribution and succession of 

 the animals is clearly correlated with evaporating power of air. By a further 

 comparison with the description of stations, Shelford shows that the evaporating 

 power of the air may be taken in this case as an index of materials, abode, 

 and the like. Since the evaporation ratios existing inside of this cage 

 filled with potato plants are greater than those obtained by Fuller for the 

 stations such as Shelford used, it appeared that L. decemUneata reared in such 



Table 7. 



a cage has a great range of adaptability. From the base of the potato plants to 

 just a little above their tops, there existed zones of evaporation of wide extremes. 

 To illustrate, Table 5 shows that from 2 to 4 p. m. at stratum A the evaporation- 

 rate was 4.6 c. c. and loss in water-weight of beetles was 7.9 per cent of their 

 entire weight; at stratum B the evaporation rate was 8.9 c. c. and loss of weight 

 of animals exposed, 13.46 per cent; and at stratum C the rate was 19.4 c. c. and 

 loss in weight of the beetles was 26.82 per cent. This shows the evaporation 

 ratios to be 1.00: 1.93:4.22, and the transpiration ratios to be 1.0: 1.7:3.4. 

 For the whole experiment, the ratios of evaporation were 1.0 : 1.7 : 3.4, while the 

 transpiration ratios were 1.0 : 1.5 : 2.4. In general, these ratios are very similar, 

 showing that there is a direct relation between the evaporation-rates and trans- 

 piration percentages, and it answers in part the question already raised: Do 



