380 



SCIENCE. 



[N. S. Vol. II. No. 38. 



righteousness — behind all seeming moral disor- 

 der and evil. I repeat, then, that whatever is 

 a necessary condition of onr highest activity — 

 whatever is contributive to the best interests of 

 our whole humanity and in the final outcome — 

 must be in some sense true. I am quite aware 

 that we are often mistaken as to what ideas 

 come under this head, but we are mistaken only 

 through a too limited and personal view. 



Therefore, in a true philosophy, we cannot 

 wholly leave out consequences. It would be ir- 

 rational to do so. ' ' But observe ; I speak of 

 consequences only as a test of truth. I would 

 not swerve a hair's breadth in absolute devotion 

 to truth. Whatever is really true will surely 

 vindicate itself as such by its beneficence, if we 

 only wait patiently for final results."* 



So much for the principle criticised. Never- 

 theless, I fi-eely admit that I may be wrong in 

 thinking that these dire consequences would 

 follow if natural selection be the only factor in 

 social evolution. There may be, and indeed I 

 am sure there is, a natural selection of fittest 

 ideas and institutions, and thereby a gradual 

 improvement of the social environment, which 

 must be a powerful factor of progress, and of 

 which I did not take sufficient account. But 

 to show that I have not been wholly unmindful 

 of this factor I quote from a recent paper :f 

 ' ' Ideas are like species. In the evolution of 

 thought, some indeed become extinct and have 

 no progeny, bvit some are transformed into new, 

 and all the new come only by such transforma- 

 tion of the old." 



Joseph Le Conte. 



Berkeley, Cal. 



THE katydid's orchestra. 

 To the Editor of Science: Possibly the 

 phenomenon I am about to describe is well 

 known to biologists, but to me it is unknown, and 

 it seems so remarkable that it is worth record- 

 ing. It is the only instance I know of in nature 

 of any continued attempt at concerted harmony 

 and measured time-keeping on the part of many 

 animals. With all the musical or sound-mak- 



* ' Evolution and its relation to religious thought,.' 

 p. 279. 



fGeol. Dep't, University of California, Bull. No. 

 11, p. 33G. 



ing capacities of animals none seems to have 

 much of an idea of measured time-beating, and 

 in no instance known to me is there any at- 

 tempt of large numbers to unite the individual 

 notes into a common musical result. The uni- 

 versal fact of preserved individualism, and in- 

 diflference to unisonal effect, is a noteworthy 

 one when we consider the high degree of musi- 

 cal sense with which some animals are endowed. 

 Probably every person would express disgust 

 at the idea of the stridulous noise of the Katy- 

 did being musical, and surprise at the sugges- 

 tion that there is any rhythm or unison in many 

 of them, but for weeks the fact has been all 

 too apparent to my family for the purposes of 

 sleep. Our house has been upon a mountain 

 top in North Carolina, surrounded by a grove of 

 trees, and farther away by woods upon all sides. 

 So soon as the sun has set and tvdlight is ad- 

 vancing, the katydids in the trees begin to 'tune 

 up.' The first notes are scattered, awkward, 

 and without rhythm, but if no wind is blowing, 

 thousands soon join in and from that time un- 

 til daylight breaks there is no intermission. It 

 is marvellous that the organs can withstand 

 this continual rubbing for eight hours. By 

 choosing out an insect close by and listening 

 to it alone I have convinced myself that the 

 same insect keeps at it at least for hours at a 

 a time. These raspings are seldom three at a 

 time, as the popular name would imply, but are 

 the result of usually four or five, sometimes six, 

 distinct but closely joined movements. When 

 united with a thousand others the disjunction of 

 these tones is, of course, not perceptible, and 

 they sound like a single note. In order to 

 make my description clearer, let vis suppose one 

 thousand Katydids scattered through the trees 

 to utter their several notes all at once, and call 

 them Company A. Another thousand, Com- 

 pany B., at once answers them, and this swing- 

 swong is kept up, as I say, all night. Company 

 A's note is the emphatic or accented note, and 

 is more definitely and accurately a precise mu- 

 sical note, whilst the note of Company B varies 

 from one to five half tones below, the most con- 

 spicuous note being five. In the old-fashioned 

 musical terms I learned as a boy. Company B's 

 note is e. g., clearly and definitely do, while 

 the note of Company B is either la, or more cer- 



