460 ENTOMOLOGICAL NEWS [ Dec., 12 
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 Stridulations of Orthoptera. 
By H. A. Atvarp, 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 Oe¢ccanthus 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. 
