63 



fourth method stridulate during flight, the others while at rest. To the first group 

 belong the crickets ; to the second the Locustarians; to the third and fourth certain kinds 

 of Acridians. AVith few exceptions the males alone stridulate. In general terms one 

 may say : 



Crickets shrill and creak. 



Locustarians scratch and scrape. 



Acridians shuffle, rustle and crackle. 



In the following pages we propose to pass in review what is known of our American 

 species in this particular, beginning with the crickets and treating the species in system- 

 atic order. In doing this we shall have occasion to make our statements perhaps a little 

 clearer by the introduction of a few illustrations, in which a peculiar system of musical 

 notation is employed. It should first of all be explained that this is done only to express 

 the time limits of the song and the rapidity of the successive notes. As the notes are 

 always at one pitch (which, when specified, has been determined by the aid of a piccolo 

 flute), there is, properly speaking, no song at all ; but it is to the insect what song is to 

 the bird, and so this tropical use of the word may here be allowed. Each bar represents 

 a second of time, and is occupied by the equivalent of a semibreve; consequently a quarter 



note I*, or a quarter rest •<, represents a quarter of a second ; a sixteenth note i*, or a 



sixteenth rest ^, a sixteenth of a second and so on. For convenience's sake I have intro- 

 duced a new form of rest ( "^ or ^ ), which indicates silence through the remainder of 

 a measure. 



Gryllidae. 



Gryllotalpa horealis Burm. This insect, our common mole cricket (Fig. 35, page 61) 

 usually begins its daily chirp at about four o'clock in the afternoon, but stridulates most 

 actively at about dusk. On a cloudy day, however, it may be heard as early as two or 

 three o'clock ; this recognition of the weather is rather remarkable in a burrowing insect, 

 and the more so as it does not appear to come to the surface to stridulate, but remains 

 in its burrow, usually an inch below the surface of the ground. The European mole 

 cricket (Gryllotalpa vulgaris), is said to chirp both within its burrow and at its mouth 

 (plerumque sub terra, Fischer says), and it may be that our species sometimes seeks the 

 air in chanting ; but the chirp, as far as I have heard it, always has a uniformly subdued 

 tone, as if produced in some hidden recess. Fischer says that the European species 

 which is twice as large as ours, cannot be heard more than from one hundred and fifty 

 to two hundred feet (w/^ra spatium 20-SO passuum). Ours, when certainly beneath the 

 surface, is easily distinguished at a distance of five rods ; and one would presume that it 

 could be heard, if above ground, nearly twice as far away. Its chirp is a guttural sort of 

 sound, like grii orgreeu, repeated in a trill indefinitely, but seldom for more than two or 



gru grfi gru grti grfi grfi gru gru grfi grQ 



Fig-ure 36— Note of Gryllotalpa borealis. 



three minutes, and often for less time. It is pitched at two octaves above middle 0, and 

 the notes are usually repeated at the rate of about 130 or 135 per minute, sometimes, when 

 many are singing, even as rapidly as 150 per minute. Often, when it first begins to chirp 

 it crives a single prolonged trill of more slowly repeated notes, when the composite char- 

 acter of the chirp is much more readily detected, and afterward is quiet for a long time. 

 When most actively chirping, however, the beginning of a strain is less vigorous than 

 its full swell, and the notes are then repeated at the rate of about 120 per minute ; it 

 steadily gains its normal velocity. Zetterstedt compares the chirp of the European species 



