114 ILLINOIS ACADEMY OF SCIENCE 



exists, but that it is subjective as regards the observer. 

 This explanation has already been suggested by Craig 

 (9) who refers also to the similar theory advanced in the 

 Dolbear-Shull controversy regarding crickets. It were 

 better to restrict the effect to that of synchronism. 



Other explanations have not been lacking. The earlier 

 writers did not hesitate to attribute to the lower animals 

 a ''fine sense of rhythm on the part of each individual" 

 (30). Both by implication and by direct statement the 

 opinion is expressed that the control of the performance 

 is consciously executed. One writer discusses the subject 

 in connection with crickets (5) : 



''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 pecu- 

 liar rhythmical chirpings of their kind, which have be- 

 come the common language of the species. If they are 

 able to recognize the notes of their kind, it is reasonable 

 to believe that the rhythmical character, as well as pitch, 

 manner of delivery, and even more subtle tonal differ- 

 ences enter into the recognition. ' ' 



It is almost gratuitous to assign rhythmic perception to 

 the lower organisms. According to Morgan it is not 

 safe to explain animal action on any higher mental level 

 than is necessary. Swindle (29) seems to think that the 

 sense of rhythm in the human species does not show 

 traces of inheritance. And the question whether savages 

 have a more pronounced sense of rhythm because, Dela- 

 croze fashion, they can often maintain complicated 

 rhythms side by side, has not yet received a final answer! 

 In the case of fireflies the added difficulty of seeing the 

 rest, except in the few instances of a spreading effect 

 from several foci (13, 22) is presented. The difficulty of 

 explaining the phenomenon on the basis of a selective 

 sex function is materially increased by the synchronism 

 itself (16). To the writer it would seem that if the flash- 

 ing is related to the sex activity of the males, as the 

 work of Mast (19) seems to indicate, it cannot be of 

 direct causal assistance, but only of secondary import- 



