570 ANNUAL REPORT SMITHSONIAN INSTITUTION, 192 8 



a file vein and scraper, is at their disposal, yet no departures what- 

 ever appear to have evolved from the simple monotone or the rhyth- 

 mic chirp in the direction of producing variety with these elements. 

 Every cricket trills unceasingly or chirps intermittently. Should a 

 cricket with tonality at its command learn to trill and chirp as 

 efficiently as the little Uhlers' katydid, or strike a series of separate 

 musical tones with the technique of the larger angular-winged katy- 

 did, cricket music would at once become a marvelous rendition of 

 tinkling tones and chimes surpassing anything we now hear in their 

 musical accomplishments. 



THE MUSICAL TECHNIQUE OF THE CRICKETS AND KATYDIDS 



It is common knowledge that crickets trill and chirp, but the tech- 

 nique of the production of the sound has been little studied. It 

 would seem that remarkable specializations have taken place, making 

 the technique of one katydid or cricket entirely unlike that of 

 another. 



In all our eastern crickets and katydids the musical apparatus has 

 been shown to be a typical file vein on one wing cover and a scraper 

 to draw over it on the other. This mechanical device seems fairly 

 simple, but the manner of using these frictional structures to pro- 

 duce sound has become very varied. 



It would appear that the sound is generally if not always made by 

 the forward stroke of the scraper or plectrum over the chitin bars. 

 The wing covers or elytra are first separated a little and set so that 

 the scraper is at one end of the file vein. They are then brought 

 together swiftly so that the scraper glides forcibly over the teeth to 

 the other end. The wing covers have now advanced to their extreme 

 closing position. When the wings are drawn back again for the next 

 note or rasp an interval of silence intervenes. It is important to 

 keep these steps in mind in an analysis and understanding of the 

 various sounds which our crickets and katydids are capable of pro- 

 ducing as their distinctive " songs " or stridulations. 



THE CONTINUOUS TRILL OR BUZZ 



The simplest and one of the most common methods of stridulation 

 appears to be that in which the scraper is run at high speed for in- 

 definite periods over the file vein. Many crickets and katydids trill 

 in this monotonous manner for hours at a time. The writer feels 

 that, in most instances, the sound depends upon the forward stroke 

 alone of the scraper upon the file vein. The slight interval of silence 

 between these jDOsitive strokes gives the noticeabje character of 

 quaver or tremolo which the trained ear can usually detect. Many 

 of our crickets have this continuous high-speed habit of stridulation, 



