To watch these frolics in the tops of the trees is hardly possible; let us try to watch them in captivity. I collect four couples in the morning and place them in a roomy cage, with a few twigs of pine. The spectacle hardly comes up to my expectations. This is because they are deprived of the power of flight. At most, from time to time, a male approaches his coveted bride; he spreads the leaves of his antennæ and shakes them with a slight quiver, perhaps to discover if he is welcome; he shows off, exhibiting his antlered beauty. It is a useless display: the female does not budge, as though insensible to these demonstrations. Captivity has sorrows that are hard to overcome. More than this I could not see. Pairing, it seems, must take place during the later hours of the night, so that I have missed the propitious moment. One detail in particular interested me. The Pine-chafer possesses a musical instrument. Male and female are similarly gifted. Does the suitor make use of his faculty as a means of seduction and appeal? Does the other answer her lover’s strophe with a similar strophe? That this happens under normal conditions, amidst the branches, is highly probable; but I should not care to say so for certain, having never heard anything of the kind among the pine-trees or in the cage. The sound is produced by the tip of the abdomen, which, with a gentle movement, alternately rises and falls, rubbing its rear-most segments against the hinder edge of the wing-cases, which are held motionless. There is no special appliance on the rubbing surface nor on the surface rubbed. The magnifying-glass searches in vain for minute ridges such as might produce a note. On either hand all is smooth. How then is the sound produced? Moisten the tip of a finger and run it over a strip of glass, over a window-pane: you will obtain a fairly well-sustained sound, not unlike that emitted by the Cockchafer. Better still: use a bit of india-rubber to rub the glass with and you will obtain a pretty faithful reproduction of the noise made by the insect. If the musical rhythm is well preserved, the imitation might deceive anybody. Well, in the Cockchafer’s apparatus, the pad of the finger-tip and the bit of india-rubber are represented by the softness of the moving abdomen and the window-pane by the plate of the wing-cases, a thin, rigid plate eminently capable of vibration. The Cockchafer’s musical instrument is thus one of the simplest. A small number of other Beetles are endowed with the same privilege. These include the Spanish Copris and the truffle-eating Bolboceras. [56] Both make a sound by means of slight oscillations of the abdomen, which gently grazes the hinder edge of the wing-cases.