[Footnote 1:  Whether the Cigale is absolutely deaf or not, it is certain that one Cigale would be able to perceive another’s cry.  The vibrations of the male Cigale’s cry would cause a resonance, a vibration, in the body cavities of other male Cigales, and to a lesser extent in the smaller cavities in the bodies of the females.  Other sounds would cause a slight shock, if loud enough, but not a perceptible vibration May not this vibration—­felt as in a cathedral we feel the vibrations of the organ-pipes in the bones of the chest and head or on the covers of the hymn-book in our hands—­serve to keep the insects together, and enable the females to keep within sight of the males?  The sight of an insect is in one sense poor—­it consists of a kind of mosaic picture, and for one insect to distinguish another clearly the distance between them must not be very great.  Certain gregarious birds and fish whose colouring is protective have a habit of showing their white bellies as they swerve on changing their direction.  These signals help to keep the flock together.  The white scut of the rabbit and of certain deer is a signal for other deer or rabbits to follow a frightened flock.  It is obviously to the advantage of the Cigale to follow a gregarious habit, if only for purposes of propagation, for this would be facilitated by the sexes keeping together, and, deaf or otherwise, the vibrations of its cry would enable it to do so.  It would be easy to show a priori that the perception of such vibrations must cause the insect pleasure, as they stimulate a nervous structure attuned to the perception or capable of the production of certain complex vibrations.  The discord of the cry is caused by the fact that it consists of a number of vibrations of different pitch.  Some would set the contents of the male resonating cavities in vibration; others would affect the less regular cavities in the thorax of the female.  We might compare the Cigale’s cry to a sheep-bell.  That it is felt and not heard explains its loudness and its grating quality.  A Cigale with the resonating cavities destroyed would possibly be lost.  The experiment is worth trying.—­[TRANS.]]

[Footnote 2:  It is not easy to understand why the Mantis should paralyse the cricket with terror while the latter will immediately escape when threatened by other enemies.  As many species of Mantis exactly mimic sticks and leaves when motionless for purposes of defence, is it not possible that they mimic their surroundings for purposes of offence as well?  It is easy and natural to say that the Mantis presents a terrifying aspect.  It does to us, by association; but how can we say that it represents anything of the sort to the probably hypnotic or automatic consciousness of the cricket?  What does it really represent, as seen from below?  A twig, terminating in a bud, with two branching twigs growing from it, and a harmless nondescript fly or butterfly perched on the back of it.  The combination of a familiar sight and a