PAPERS ON ZOOLOGY 



269 



sllo^^^l that the yellow race has successfully settled in 

 tropical regions which have 50 inches of rainfall. He finds 

 that north Australia possesses some area of this sort 

 which is not suited for settlement for the white man and 

 Australia has excluded the yellow race from that which 

 Australia cannot itself make use of. From these brief 

 remarks I hope that I have made clear what is very evi- 

 dent to me, namely, that in dealing mth insect pests, 



Fig. 6. Hythergraphs or rainfall-temperature charts of several lo- 

 calities. The figures at the top of the chart represent rainfall in inches. 

 The vertical scale is degrees Fahrenheit. The heavy black line repre- 

 sents the rainfall temperature conditions in the Australian tropics. The 

 horizontal rulings fill the space within the plot for Calcutta which 

 is in the center of tropical cotton production; the vertical lines fill 

 the space within the plot for Juiz, Brazil, the center of hill coffee pro- 

 duction. One concludes that the Australian tropics are good for cotton 

 but not for hill coffee. The curve with crosses at the angles is for 

 Bloomington, Illinois. 



