63 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 1 



0°C. 5°C. 10°C. 20°C. 30°C. 40°C. 50°C. 



Hypothetical Curve...- 



I Terrapin Heart Curve.. 



I Thermal Constant Curve 



I Toad Tadpole Curve.... 



' Frog Muscle Curve 



\ Cat H^s^^'t Curve 



'. Frog Tadpole Curve.... 



\\ 

 W 



►Critical Point. 



r>r'tHmum.'> 



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Figure 2. Captiou ou opposite page. 



