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THE AMERICAN NATURALIST [Vol. LI 



sponse tends to bring the chirping of many individuals 

 into a regular synchronism, but I feel, also, that the 

 crickets are somehow unconsciously influenced by one an- 

 other in their chirpings so that they tend gradually to 

 build up a common sjTichronic rhythm as the night ad- 

 vances. Once a sjTichronic rhythm is established, I am 

 inclined to feel that it would be natural for those indi- 

 viduals which began chirping, at first asynchronously, to 

 chirp, sooner or later, in unison with their fellows. 



From the tone of certain discussions which have taken 

 place in Science for the past several months, it is clearly 

 indicated that the synchronous flashing of fireflies as a 

 reality is somewhat doubted. There is no reason to con- 

 sider such synchronism ''contrary to all natural laws," 

 as Laurent as recently stated in Science for January 12, 

 1917. In the tropics it appears that great numbers of 

 fireflies frequently establish themselves in the crowns of 

 certain trees, and I am not at all ready to deny that under 

 certain conditions such cohmies may not flash sv^lchro- 

 nously, as reported by Cunningham {loc. cit.), Shelf ord, 

 and otliers. It is unfortunate that in most instances these 

 re])orts are accompanied ))y very meager details as to tlie 

 general behavior of the fireflies in these arl)()i-eal colonies. 

 Cuthbert Collingwood, however, in lii> hook, "liniiiblcs 

 of a Xaturalist," {18()8), pp. 254 25:). h;i^ -ivcn .-i very 

 careful account of his observations of llic syiichioTious 

 flashing of fireflies, as follows: ''At Sin^nporc ;iml also 

 at Tiahuan, the little luminous beoth> coiiitnodly known as 

 th." fin-tly I L<nni>i/ri>' Sp. f,/,/.) \- coninu./i. When flying 

 sinu'ly it -hint's with an intci'tnittcnt liu'ht wliich alternates 

 withdarknc-- hnt nn line cvrnin-- nii.l in I'nvorable (i. e., 

 dani)) and swain|)\ ) !(»-;itions. pi-c-ciil a very re- 



markable ai)jjearaii<'('. rliivii.rcd in the t'.ilinuv of tiie 

 trees, instead of kccpin-- np ;in i n'^u-uh-i i' twinkh'. cNcry 

 individual shine- -ii!inltaiicnn-;\ \\\ rci:-uhn- inter\-al>. ;is 

 thnii-li h\ ronniicn inipniM.; ll.rir li-ht pulsates, 



ii- it wnv. and t'-.r tiv.- i- h,r .m.- ni..„,Mit illuminated by 

 a 'MiUKhv.j !.i-iHi:in1 point- :ind tiw iic\t i- in almost total 



