SONG IN INSECTS. 
721 
musical organs with specially adapted muscles. We cannot in this place 
deal exhaustively with such a subject nor even discuss the extremely 
interesting Indian songsters more than extremely briefly; the curious 
reader will find fuller details in the papers mentioned. 
Acridiidce do make sounds but, in our experience, only rarely. We 
have never heard the migratory locust make a sound, and after prolonged 
observation we learnt that only when in the act of mating does the 
Bombay locust emit a feeble chirp, produced in the usual manner by 
rubbing the hind femur against the tegmen. It is rare that Acridiidce 
make sounds in any other way. (See Autarches.) Far more noisy in 
India are the Locustidce, some species of which keep up a shrill noise in 
grass while others make noises of various kinds in trees. In the Locus¬ 
tidce, the male has the base of the tegmina flattened, that of the upper 
(right one) with a sharp point which works on a file on the lower (left) ; 
as the wings are moved, the vibration is set up, its pitch and intensity 
determined by the length and tension of the tegmen, and so a note 
produced. Conocephalus indicus is probably the species most commonly 
heard, its shrill note in the grass always appearing to be a little distance 
off but never in any one definite direction. Gryllidce are often trouble¬ 
some from the shrillness and persistency of their song ; the sound is 
produced by the vibration of the forewings on the hind wings and one 
can see the wings and tegmina in a state of vibration when the insect 
is engaged in song. The large Brachytrypes achatinus makes a sound 
which is extremely powerful and, when close, almost unbearable. It is 
the loudest songster in the plains where Cicadas are scarce. 
Dragon flies are said to produce sounds by a process in the large 
trachea being thrown into vibration by the passage of the air, but we 
are not aware that this has been noted in Indian species. 
Among Hvmenoptera, Mutilla squeaks by the friction of the abdo¬ 
minal segments, Lohopelta, Sima and other ants by friction of the 
peduncle and basal abdominal segments, and bees (by the vibration of 
the wing if this can be called a sound and) by mechanism connected 
with the respiratory system, whereby the hum heard in a bee-hive 
is said to be produced. 
In beetles, sound-production occurs in both sexes, as well as in 
some larvae, and there are excellent accounts of the mechanism in 
different beetles. Anohium is said to tap with its head ; the friction 
of the jaws of some longicorn larvae in dry wood is quite audible in 
some cases. Gahan describes stridulating organs in almost every part 
of the body in beetles ; perhaps the most familiar instances are those 
large Cerambycid beetles (such as Batocera rubra) in which the hind 
edge of the pronotum rubs on a file on the mesonotum. The reader 
should consult Gahan’s article (Trans. Ent. Soc, Bond. 1900, p. 433) 
and Arrow’s article on “ Sound Production in the Lamellicorn 
Beetles.” (Trans. Ent. Soc. Bond. 1904, p. 709.) It is worth noting 
that in Coleoptera, the stridulating organs commonly occur in both 
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