THE CANADIAN ENTOMOLOGIST. 



221 



cr other external conditions, at the same time shows individual peculiarity 

 in rate, so that under the same conditions the rate is constantly higher or 

 lower than that of other crickets, this constant peculiarity might be 

 referred to as "rate individuality." 



To determine whether individuality affects rate as I found it to affect 

 pitch and quality of chirp, several crickets were confined in the house. 

 But they rarely chirped, and then for but a short time. Outside in the 

 yard and fields it was found that chirps issued from the same point in the 

 bushes evening after evening. Sometimes these chirps possessed 

 peculiarities of pitch or unsteadiness which were different from those of 

 almost any other cricket. When these peculiarities occurred in the same 

 place for several successive evenings, I assumed that they were produced 

 by the same cricket. The data given in Table IV are from one such 

 cricket, whose distinguishing peculiarity was an interrupted chirp, 

 accentuated at the beginning and end as if the wings were then pressed 

 more firmly together, so that the chirp sounded almost as if divided in 

 the middle. 



Table IV. — Showing rates of chirping of same individual of 

 CEcanthus niveus over a period of thirteen days : 



Date. 



Aug. 23 



Aug. 24 



Aug. 27 



Aug. 28 



Aug. 29 



Sept. I . 



Sept. 2 . 



Sept. 4. 



Number of chirps per 

 minute of the same in- 

 dividual of CEcanthus 

 niveus on different davs. 



149 



167 



80 



80 



109 



•05 

 149 

 IOC 



Temperature in degrees Fahrenheit. 



These data, together with data secured in like manner from two 

 other crickets, are graphically represented in fig. 15. The straight solid 

 linf is the representation of Dolbear's formula. The other solid lines, 

 A and B, are from two crickets that were observed over nearly the same 

 period of days, one cricket being that referred to in Table IV. The two 

 crickets were at nearly the same elevation and in similar locations; so that 

 external conditions were practically identical. The dotted line is the 

 curve for a cricket observed over a different period of time. 



