MORSE: ORTHOPTERA OF NEW ENGLAND. 237 
characteristic of most flying species but is not to be regarded as 
purposeful sound production. Sometimes a high-pitched piping 
note is sounded by bees and flies by the vibration of membranes 
at the openings of the spiracles when acted on by a current of 
air, — a type of sound thus akin to our own voices. The cicada 
produces his shrill 2;ee-ing or buzzing notes by vibrating a tense 
membrane by means of powerful muscles working on the prin- 
ciple of the ' devil's fiddle. ' 
In by far the larger proportion of cases, however, insect sounds 
are produced by stridulation, a rubbing of one part of the body 
on another. As might be expected in creatures of such varied 
and complicated structure there are wide differences in the 
details of its production with reference to the parts of the body 
involved, and in the quality of the sound produced. 
Among our New England Orthoptera sound is produced, as a 
rule, only by the adult male, though the female sometimes makes 
it in lesser degree. Since both sexes are equipped with auditory 
organs and respond to the sound produced, it is presumably use- 
ful as a means of communication, and especially of attraction of 
the female by the male. Males often stridulate, however, appar- 
ently in rivalry, in play, or from the mere joy of living, after pair- 
ing has been completed; and occasionally the sound produced is 
used defensively when attacked, e. g., in the cases of the Katy- 
did (Pterophylla camellifolia) and the southern Lubber Grass- 
hopper (Rhomalea) which respectively squawk and hiss when 
touched or about to be seized. 
The chief methods of sound production among Orthoptera are 
three in number: 1st, by rubbing certain parts of the bases of the 
wing-covers together, — this is the method used by the Crickets, 
Katydids, and Long-horned Grasshoppers; 2d, by rubbing the 
hind thighs against the closed wing-covers, — this is done by some 
kinds of Locusts; 3d, by beating the wing-covers with the front 
edge of the wings while flying, — this method also is characteristic 
of some kinds of Locusts, the Oedipodinae particularly^, and in 
many cases the two latter methods are used by the same insect. 
It is not unlikely that marked variations of these, or even 
additional methods, are employed in some cases by our 
New England species, as is known to be true of some exotic 
Orthoptera. 
