SHORTER ARTICLES AND DISCUSSION 



RHYTHMIC SYNCHRONISM IN THE CHIRPING OF 



CERTAIN CRICKETS AND LOCUSTS 

 Synchronism in the rhythmic chirping of the snowy tree 

 cricket, (Ecanthus niveus De G., has been observed and men- 

 tioned by a number of able observers, including Burroughs, 

 Thoreau, McNeill and Dolbear. The synchronous chirping of 

 this particular cricket has been too generally observed to be con- 

 sidered merely an illusion of the mind. In a previous paper 1 

 I reported that I had observed the occurrence of rhythmic syn- 

 chronism in the chirping of colonies of the tiny tree crickets. 

 Ciirtori/Jxi col umbimni Caudell in Georgia. During the sum- 

 mer of 1917 I was afforded an excellent opportunity to make 

 further observations of the synchronous chirping of these inter- 

 esting arboreal crickets near Vinson Station, Virginia. A little 

 colony had become located in the crown of a small black cherry 

 tree in my back yard, where I could readily keep them un.'er 

 observation at all times. During the latter part of August, 

 when the chirping season was at its height, a remarkable degree 

 of synchronic rhythm characterized their chirpings during 

 warm, quiet evenings. So constant, was this rhythmic syn- 

 chronism that only now and then would any irregularity occur. 

 It finally occurred to me that I could subject their consecutive 

 chirp inns to a fairly accurate statistical analysis in the follow- 

 ing manner. With a tablet of paper and a pencil I made a short 

 horizontal dash for those instances when the chirpings were in 

 unison, and a short vertical dash when they were not in unison. 

 In this way I was able to record the consecutive chirpings for 

 certain periods of time. In order to illustrate this method, I 

 will give a graphic expression of the first period, which included 

 98 consecutive chirpings, 8 of which were not in unison. 



Fourteen different periods of consecutive chirpings were re- 

 i " Synchronism and Synchronic Bhythm in the Behavior of Certain 

 Creatures," Am. Nat., Vol. 51, July, 1917. 



548 



