INSECT INSTRUMENTALISTS ALLAKD 585 



its notes, each made with one draw alone of the scraper across the 

 file vein. These notes are very brief, to be sure, scarcely more than 

 mere dots or points of sound, but they are as smooth and as ringing 

 and scintillant as tones struck on glass or upon a xylophone. Marvel- 

 ous is the uniformity of life, however, when, of all the hundreds of 

 thousands, perhaps millions, of crickets I have listened to in my ex- 

 perience, so few have failed to chime anything but the distinctive 

 notes of the species. These rare instances, however, represent poten- 

 tialities within the attainment of the creatures, and potentialities 

 somehow seek their fulfillment with strange insistence at every turn. 



PHYSIOLOGICAL SPECIES AND THEIR STRIDULATION 



Our established systems of classification recognize specific differ- 

 ence mainly on the basis of morphological distinctiveness. This 

 basis works fairly well at times, but at other times the criterion 

 appears to be poor and uncertain. The forces of life are not working 

 on the basis of definitely predetermined concepts resting upon a 

 structural or morphological basis alone, but deep down in the physio- 

 logical complex as well. The field naturalist is doomed to despair 

 so soon as he accepts as clear-cut and final most morphological con- 

 cepts of the patient laboratory analyst. The more intensively we 

 stud}^ the localized facies of life, the more do we find varietal dis- 

 tinctiveness, racial distinctiveness, on and on, even to individual 

 distinctiveness. The big field cricket, Gryllus assimilis^ may show no 

 obvious morphological distinctiveness in the region between Massa- 

 chusetts and Georgia, yet in the Georgia piedmont district near 

 Gainesville I found an early spring race of this cricket with a habit 

 of weak, continuous trilling, reminding one of the trill of the four- 

 spotted tree cricket, Oecanthus nigricornis quadripunctatus. Even 

 the behavior of these crickets has a physiological distinctiveness, for 

 they appear very reclusive, living in holes and burrows under the 

 clods. Later, when the great midsummer broods appear, this con- 

 tinuous trilling form disappears, and the typical chirping form 

 replaces it. 



I have likewise found a most marked departure in the tiny bush 

 cricket, Anaxi'pha exigua-. An early physiological race appearing 

 in May and June, and confined entirely to dead ground — debris of 

 the low, wet, grassy bogs of meadows and swamps — has the habit of 

 prolonged trilling. The great typical assemblage which appears in 

 August clings to the higher, drier zone of upland herb and shrub, 

 and produces a thin, shrill, intermittent chirp, usually by the single 

 wing stroke I have previously described. Morphologically the clas- 

 sificationist can find nothing to distinguish these physiological forms 

 from the typical species assemblage. Yet they exist, because nature 



