

This range is different i'>r liriVn-m in 



cut seasons <>r places, and is dillci cnl r\m for different individii 

 llic sami under ;ipi>;ircnl ly f(|u;d < < mdit i >n -. ;ind for dil 



3 in thf Drouth or development of the same individual. The 

 temperature ran^e i> at'fei ted by food, moistm 



leveral other t'ai : 



( i row th and df \-flopnu-nt proceed mo>t rapidly in a < crtain optimum 

 ran^f of temperature, within which there is, at lca>t theoretically, an 

 optimum decree of temperature. At and above a certain degree of 

 hi^h temperature heat-rigor sets in, and may or may not be fatal to an 

 organism, according to the duration of the exposure to the temperature. 

 This maximum temperature has as its upper limit the ultramaximum , 

 at which the organism dies at once, probably because of the coagulation 

 of proteids in the protoplasm. At a certain degree of low temperature, 

 cold-rigor takes place; the point at which it occurs being near the freez- 

 ing point, on account of the fluid content of protoplasm. Below this 

 minimum is an ultraminimum temperature, at which the organism dies. 

 The following examples of temperature-limits are from Davenport's 

 Experimental Morphology. 



INSECT MAXIMUM ULTRAMAXIMUM 



Springtail, Podura similata ............. ............... 27 C. 36 .0 C. 



Mosquito, Culex pipiens ............................. 40 C. ........ 



Larva of fly, Musca vomitoria ......................... ...... 42 . 5 C. 



Pupa of fly, Musca vomitoria ............... : .......... ..... 43 . 7 C. 



Silkworm, Bombyx mori .............................. ..... 42 . 5 C. 



Back-swimmer, Notonecta ............................. ..... 45 . o C. 



It should be noted that the Podura (near Achorutes) has a thin 

 integument, and can not live in a dry atmosphere. The pupa of the 

 fly is protected somewhat by its puparium, and the back-swimmer by 

 a fairly thick integument. 



INSECT ULTRAMINIMUM 

 Honey bee, Apis mellifera .............................. ........... i . 5 C. 



House fly, Musca domestica ....................................... 5 . o C. 



Lurva of cockchafer, Melolontha ...... .-. ........................... 15.0 C. 



Adult cockchafer, Melolontha ...................................... 18 . o C. 



Davenport notes that the large size and thick covering of the beetle, 

 Melolontha prevent the rapid loss of heat. 



< Activity in Relation to Temperature. The range of activity of the 

 adult cotton boll weevil lies between 56 F. and 95 F. From 95 to 

 122 is the range of aestivation, within which the beetles are inurti\v . 

 From 122 to 140 (soil temperature) is an upper range of fatal lem- 



