460 ENTOMOLOGICAL NEWS [Dec., 'l2 



takes the sense in which I have used the term oligotropic. I 

 think it will be found that C. brevicornis does not collect pollen 

 of any of the plants he mentions, except Campanula, and that 

 would not be unexpected in the case of a supposed oligotrope 

 of Specularia. 



Variation in the Stimulations of Orthoptera. 



By H. A. ALLARD, U. S. Dept. of Agriculture, 

 Washington, D. C. 



Many musical Orthoptera may be readily identified by their 

 characteristic stridulations. It must be remembered, however, 

 that all individuals of a given species do not always stridulate 

 in quite the same manner. The usual stridulations may be 

 more or less modified by a variety of external conditions, or 

 even voluntarily changed from time to time by the insect. 

 These differences may be classed as individual, accidental, 

 local or geographic and volitional. 



Independent of optimum conditions of existence, individuals 

 of the same species or variety always show considerable varia- 

 tion in the intensity and rapidity of delivery, but more espe- 

 cially in the pitch of their notes. These differences are in- 

 herent in the individual make-up of the insect. 



Inherent individual peculiarities of stridulation are likewise 

 considerably modified by accompanying atmospheric condi- 

 tions, especially temperature and moisture relations. Variable 

 modifications of this sort are accidental in the life of the in- 

 sect. Among the crickets these accidental modifications are 

 more especially noticeable in the notes of intermittent trillers, 

 such as Oecanthus niveus DeG., Oecanthus angustipennis 

 Fitch, Cyrtoxipha columbiana Caudell, Orocharis saltator Uh- 

 ler and others, since the rate of delivery of the successive 

 trills is quite dependent upon attending temperature condi- 

 tions. In general, higher temperatures stimulate brisk, rapid 

 trillings, while low, unfavorable temperatures diminish the 

 intensity and rapidity of the notes. The pitch, however, is not 

 materially changed. 



