December, ' 14] HEADLEE: EFFECTS OF TEMPERATURE AND MOISTURE 



415 



Table Showing the Effect of Temperatcre Changes on the Rate of Metabolisu in Certain Insect SpEcres 



In this connection, the relation between the effect of constant tem- 

 perature and of average means should be pointed out. The accom- 

 panjdng table shows that the constant temperature is much the more 



powerful, considerably shortening the growth stage and length of life 

 and increasing the daily rate of reproduction, and when taken -wdth 

 the preceding table also shows that, except in reproductive activity, 

 the rate of increase for the twenty degrees of change from 60°F. to 

 80°F. is practically the same under the average mean as under the con- 

 stant conditions. 



^Moisture 



The effect of moisture on the rate of insect metabolism has received 

 much less attention than has the effect of temperature. Davenport,^ 



^ Davenport, C. B., Experimental Morphology', vol. II, p. .360. 



