No. 607] RHYTHM IN BEHAVIOR OF CREATURES 443 



various observers. On the supposition that the rate of 

 chirping of these crickets is entirely a function of tem- 

 perature, it has even been considered that the crickets 

 may serve as an accurate thermometer. As temperature 

 indicators, however, the crickets can not always be relied 

 upon under all conditions, since wind, humidity, and elec- 

 trical conditions of the atmosphere preceding thunder- 

 storms, also appear to influence the activities of these in- 

 sects. 



It is now a question as to whether these crickets per- 

 ceive the rhythm which is so pronounced in the regular 

 sequence of their chirpings. I believe they must, for it is 

 quite evident that they hear and respond to the peculiar 

 rhythmical chirpings of their kind, which have become 

 the common language of the species. If they are able to 

 recognize the notes of their kind, it is reasonable to be- 

 lieve that the rhythmic character, as well as pitch, manner 

 of delivery, and even more subtle tonal differences enter 

 into the recognition. 



The rhythmic chirping in unison which oftentimes be- 

 comes such a pronounced feature in the music of these 

 crickets takes place only in the evening and appears to 

 depend upon the nice adjustment of certain nocturnal 

 atmospheric relations— moonlight, temperature, humid- 

 ity, and stillness of the air. Early in the evening, per- 

 haps, a siii.uh- crickot licuins its stridulations which stimu- 

 late others to respond, and hy degrees the great chirping 

 chorus is augmented. There may be no noticeable syn- 

 chronism in the chirping at first, but if conditions are 

 favorable, the crickets gradually build up a synchronic 

 I'hythm until waves of solemn music are produced by a 

 certain colony. 



There seems to be a marked tendency for the indi- 

 viduals of each colony to adopt the rh>i;hmic beat of their 

 particular colony, so that not infre<iuently a neighboring 

 colony may <'sta"l)1i<li an antiplional rliytliin. with the re- 

 sult that \va\c> nf ( jiiavcring sound -winii' backward and 



How is till.- -yndii-onal cliii-pinu' built up and main- 

 tained? It pi-nbaMr that tlu^ instinctive habit of re- 



