ANATOMY AND I'll VSK >!,< H,Y 



93 



In ( )rth<>i>trra, the fn-cjiirm y <>!" ^t nMul.it i.,n increases with t 

 [trratutv; and t he o.nrlatinn Ix-t w.-ni t h< o close that it is easy 



:& 



ff- 



B 



FIG. 138. Stridulating organs of Microcentrum laurifolium. A, dorsal aspect of 

 file (st) when the tegmina are closed; B, ventral aspect of left tegmen to show file; C, dorsal 

 aspect of right tegmen to show scraper (s). 



to compute the temperature from the number of calls per minute, by 

 means of formulae. The formula for a common cricket [probably a 

 tree-cricket, (Ecanthus niveus], as given by Professor Dolbear, is 



T = 50 + , which simplified is T = 40 + * 



4 4* 



Here T stands for temperature and N, the rate per minute. 



A similar formula for the katydid (Cyrtophyllus pcrspicillatus), 

 based upon observations made by R. Hay ward, would be 



60 



A' - 19 

 3 



Here, in computing A 7 , either the "katy-did" or the "she-did" is t 

 as a single call. 



