If the weather is calm and hot, towards mid-day the song of the Cigale is divided into strophes of several seconds’ duration, which are separated by brief intervals of silence.  The strophe begins suddenly.  In a rapid crescendo, the abdomen oscillating with increasing rapidity, it acquires its maximum volume; it remains for a few seconds at the same degree of intensity, then becomes weaker by degrees, and degenerates into a shake, which decreases as the abdomen returns to rest.  With the last pulsations of the belly comes silence; the length of the silent interval varies according to the state of the atmosphere.  Then, of a sudden, begins a new strophe, a monotonous repetition of the first; and so on indefinitely.

It often happens, especially during the hours of the sultry afternoons, that the insect, intoxicated with sunlight, shortens and even suppresses the intervals of silence.  The song is then continuous, but always with an alternation of crescendo and diminuendo.  The first notes are heard about seven or eight o’clock in the morning, and the orchestra ceases only when the twilight fails, about eight o’clock at night.  The concert lasts a whole round of the clock.  But if the sky is grey and the wind chilly the Cigale is silent.

The second species, only half the size of the common Cigale, is known in Provence as the Cacan; the name, being a fairly exact imitation of the sound emitted by the insect.  This is the Cigale of the flowering ash, far more alert and far more suspicious than the common species.  Its harsh, loud song consists of a series of cries—­can! can! can! can!—­with no intervals of silence subdividing the poem into stanzas.  Thanks to its monotony and its harsh shrillness, it is a most odious sound, especially when the orchestra consists of hundreds of performers, as is often the case in my two plane-trees during the dog-days.  It is as though a heap of dry walnuts were being shaken up in a bag until the shells broke.  This painful concert, which is a real torment, offers only one compensation:  the Cigale of the flowering ash does not begin his song so early as the common Cigale, and does not sing so late in the evening.

Although constructed on the same fundamental principles, the vocal organs exhibit a number of peculiarities which give the song its special character.  The sound-box is lacking, which suppresses the entrance to it, or the window.  The cymbal is uncovered, and is visible just behind the attachment of the hinder wing.  It is, as before, a dry white scale, convex on the outside, and crossed by a bundle of fine reddish-brown nervures.

[Illustration:  1.  THE ADULT CIGALE, FROM BELOW.

2.  THE ADULT CIGALE, FROM BELOW.

3.  THE CIGALE OF THE FLOWERING ASH, MALE AND FEMALE.]

From the forward side of the first segment of the abdomen project two short, wide, tongue-shaped projections, the free extremities of which rest on the cymbals.  These tongues may be compared to the blade of a watchman’s rattle, only instead of engaging with the teeth of a rotating wheel they touch the nervures of the vibrating cymbal.  From this fact, I imagine, results the harsh, grating quality of the cry.  It is hardly possible to verify the fact by holding the insect in the fingers; the terrified Cacan does not go on singing his usual song.