446 



THE AMERICAN NATURALIST 



[Vol. LI 



could be adduced, however, than to attempt to determine 

 the reality of synchronism in a colony of chirping tree- 

 crickets from statistical results obtained for only two 

 crickets of the colony. That synchronous chirping may 

 be a reality, it is not necessary that 100 per cent, of the 

 individuals of a colony chirp exactly in unison. A few 

 crickets chirping asynchronously would not necessarily 

 prove that a synchronism did not exist. As a matter of 

 fact, some individuals always chirp asynchronously, even 

 when the s^Tichronic rhytlim is most pronounced. Taking 

 any two crickets from such a colony, the results would 

 depend entirely upon which two crickets were chosen, and 

 either perfect synchronism or absolutte lack of synchro- 

 nism, would be established. 



It is obviously impossible to subject all the individuals 

 of a colony of chirping tree-crickets or a group of flashing 

 fireflies to statistical analysis. Because this is impossible, 

 however, one is not justified in concluding that judgment 

 based upon careful observation is of no value in deter- 

 mining the reality of synchronism. If one hundred men 

 were marching down a street and 75 were in step while 25 

 were not, judgment alone would establish the fact that a 

 synchronic rhythm existed. This would be quite as true 

 for the chirping of tree-crickets or the flashing of fireflies. 

 As a matter of fact some of the most marvellous dis- 

 criminations depend upon niceties of judgment alone, and 

 no amount of statistical data would simplify the matter. 



I can not yet agree with those who are inclined to be- 

 lieve that the snowy tree-crickets never chirp synchro- 

 nously, and that it is impossible for fireflies to flash s^^l- 

 chronously, especially certain tropical species of fireflies, I 

 will agrees however, that in practically all instances of 

 syii<-lir<.ni<- rliytlmi iIhmv H>.'m.^ to l.c ih> (.vi.hMice of con- 

 s<'ioiis. intcnlidiial iiintatioii, but merely instinctive, reflex, 

 or automatic rear-tions to certain stimuli, similar in many 

 respects to the unconscious reactions of the leaves and 

 leaflets of the sensitive plant. 



