Nos. 622-623] SHORTER ARTICLES AND DISCUSSION 549 



corded in this manner, the results of which may be noted in the 

 following table: 



TABLE I 



From these data it would appear that out of a total of 870 

 chirpings observed, 92.8 per cent, were in unison. Even grant- 

 ing that some errors have been made in these determinations, 

 it is quite evident that this observed high percentage indicates 

 that a remarkable degree of synchronic rhytl o irs 



I kept this particular colony of four or five crickets under 

 observation for a long fcinie, and this rhythmic synchronism was 

 always very noticeable. These crickets chirp most actively just 

 before sundown. At this time every individual chirps briskly, 

 and it is not long until chirping in unison is gradually estab- 

 lished. This rhythmic synchronism does not take place at once, 

 but becomes evident after the crickets have been chirping steadily 

 for some time. When this rhythmic unison is fairly estab- 

 lished it appears difficult for the crickets to chirp otherwise, for 

 if there is any tendency toward asynchronous chirping, it is 

 quickly overcome. A remarkable feature of the chirping of 

 these crickets is a tendency now and then for the chirping to 

 become noticeably accelerated briefly. Even though this occurs, 

 the entire group keeps pace, so that the same unison is main- 

 tained. 



The mole cricket (Gryllotalpa borealis Burm) is not an uncom- 

 mon species in low grounds in this part of the country. Its notes 



