550 



THE AMERICAN NATURALIST [Vol. LII 



are low, mellow, intermittent chirpings— gur-r-r-r-r, gur-r-r-r-r. 

 gur-r-r-r-r— which may be kept up almost incessantly during the 

 active mating season. I have never been able to observe any 

 definite rhythmic synchronism in the chirping of these burrow- 

 ing crickets. However, late in August, during the season of 

 1918, 1 attempted an analysis of the notes of two of these crickets 

 which were stridulating at the same time in their underground 

 burrows in a wet spot near Vinson station. Virginia. These 

 two individuals chirped very persistently, and at times I noted 

 some degree of synchronism. 



TABLE II 



Statistical Analysis op 10 Different^ Periods of Consecutive Chirp- 



Total 1 424 , 222 I 202 j 52.3 



From these data, which indicate that out of a total of 424 chirp- 

 ings only 1222. or .V2.:i per cent., were in "unison, it would appear 

 that there was no particular tendency to maintain a definite 

 synchronism in their chirpings. 



The most remarkable instances of rhythmic synchronism I 

 have ever heard have been afforded by the cone-headed grass- 

 hopper of the species Neoconocephalus exiliscanorus (Davis). 

 A careful study of the intermittent notes — zeet-zeet-zeet-zeet — 

 of these locusts was made on the edge of a swamp near Vinson 

 Station. Virginia, late in August, 1917. 



The characteristic habit of s^ridulation for individuals of 

 this species is to produce a certain number of consecutive notes, 

 followed by a brief pause. Usually, from fifteen to thirty con- 

 secutive notes are delivered before the pause takes place, then 

 stridulation is again resumed. Rehn and Hebard 2 mention th\< 

 habit as follows: 



2 Rehn, James A. G., and Hebard, Morgan, "Studies in American Tet- 



