if^ % 



Y* 



PSYCHE. 



ORGAN OF THE CAMBRIDGE ENTOMOLOGICAL CLUB 



EDITED BY B. PICKMAN MANN. 

 Vol. I.] Cambridge, Mass., October, 1875. [No. 18. 



The Chirp of the Mole-cricket. 



The common mole-cricket of the United States (Grytlotalpa 

 borealis Burm.) usually commences 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 thi'ee o'clock : this recognition of the weather is rather 

 remarkable in a burrowing insect, and the more so since 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 is said to chirp both within its bur- 

 row and at its mouth (plerianque 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 (ultra spatium 20-30 passuum). Ours, when 

 certainly beneath the surface, is easily distinguished at a dis- 

 tance 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 gru or grveu, re- 

 peated in a trill indefinitely, but seldom for more than two or 



gru gru grit gru grfi grfi gru gru gru gru 



|— 0-9-0-0-0-0.-O ~H#-* 0-p-»j-»-[-?-4-*-?- ) >,-9-?-\-*,-*-*-*,-+-f-Z 5 I f ? *~ ' 



n p?i i^i/i $\ z>t\ ip0i \>t\ \>\t\ pti pgirs l, 



three minutes, and often for a less time. It is pitched at two 

 octaves above middle C, 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, 



