No. 607] RHYTHM IN BEHAVIOR OF CREATURES 



439 



may be followed by thousands. Although the seventeen- 

 year cicada rarely sings at night, Hopkins^ noted a most 

 remarkable nocturnal concert which began with a single 

 singer. He says: 



I was fortunate enough to hear the starting of one of these concerts 

 on a clear, moonlight night in June. One male in an apple tree near 

 the house suddenly called out as if disturbed or frightened. ^ His 



where it was "taken up by thousands of singers,°and the concert was in 

 as full blast as if it liad been the previous day. This continued a few 



its highest pitch, when it began to gradually subside, and in a short 



In his book, "Bolivia" (1914), Paul Walle (p. 268) 

 speaks of the sudden outbursts of noise in the tropical 

 wilderness as follows : 



As the darkness grows deeper, the silence of the forest is broken 

 by the sound of flight, by sudden rustlings, or by a strident shriek. 

 Immediately the creatures of the forest raise their various cries, the 

 uproar lasts for a moment, and all relapses into a silence in which one 

 still hears, more or less sensibly, the murmur of a million insects. 



In such instances where a group of creatures respond 

 simultaneously to the same initial stimulus, we have the 

 simplest case of s\Tichronic behavior. I once witnessed 

 an instance of a similar synchronic behavior in the move- 

 moiits of a colony of ]ilant lice which thickly covered the 

 till of a twiu-. \Vliile 1 was watching them, a tiny, para- 

 sitic \va>]) a]»|>i-oaehed and hovered over the 

 colony preparatory to attacking them. The plant lice 

 became aware of it> inTsence and in an instant tlio entire 

 colony raised the hind jioi'tion of theii- hodie> simul- 

 taneously into tlie ail- at an an-'le of alumt 4.") and began 

 waving their hind le-'> ai)oiit. Thi> bflia\ior wa> prob- 

 ably more or less a pi-oterti\-e n">pon>i' lo the primary 

 stimulus afforded by Ihr presence of tlie wa^p. It i> also 

 possible that the reaction, once started in a few iixlivid- 



. Dept. of AgT., 189», ] 



