The same observers then go on to tell us that if white ants are disturbed in any sudden way, as by the too rough shaking of their nest, or by a light being suddenly flung upon it, or if otherwise annoyed, “all the members of the colony begin to quiver, except those that are running briskly about in search of a better situation.”[9] When dying, too, they will sometimes quiver in this way, at intervals of a few minutes, for as much as an hour or two, or even longer. Should an enemy—such as those we have been speaking of—be introduced of a sudden into the nest, the less valiant members of it prefer to run away, but in the midst of their retreat they may often be seen to stop and quiver with unusual energy. Their object in these cases seems to be to raise a general alarm, nor is it long before they are successful. Again, if whilst one insect is burrowing into wood another outside should quiver in this way, the burrower quickly comes out, as though in response to some signal of alarm. From all this it seems evident that these curious movements must be accompanied by some sound, or sounds, inaudible to our human ears, and perhaps having a varied range, and with considerable power of modulation. To produce them, however, some stridulating or other organs would seem to be necessary, and of these, though they must, if there, be visible under the microscope, Professor Grassi says nothing. Possibly, however, sounds may be produced by the rubbing together of various parts of the body without any special apparatus having been developed, in which case the language, if we may call it so, cannot be so rich or copious.