Haswell (Pro. Linn. Soc. N.S.W. 1886) describes it thus: “The loud shrill note emitted by the insect is the result of a quick succession of crackling sounds produced by the movement of the stiff membrane with its horny ribs, through the agency of the muscle. Under ordinary circumstances, the sounds follow one another with sufficient quickness to produce a continuous note, and this is effected not by the contraction of the muscle as a whole, but by the successive contraction of individual _fasciculi_ (different filaments forming the whole), all of which act on the horny plate, and thus the movements of the muscle on the tendon during the production of the note resemble those of the hammer-board of a piano when a number of keys are being struck in quick succession.” The life history of cicadas has attracted much attention; on first emerging from the eggs they might easily be taken for minute shrimps, apparently all heads and claws. They cast themselves off the branch and, falling to the ground, burrow into the soil and follow down the roots, where they feed upon the sap and undergo a series of moults. We do not know the length of time that they take to develop underground, but the adults of several of our large species, though each year more or less in evidence, appear in greater numbers every third year, so that it is probable that three years is about the cycle of their subterranean existence. The grotesque pupa burrowing upward when fully developed, bores a vertical shaft often several feet long before it comes to the surface, when it crawls out and climbs up the nearest tree trunk or fence, where it clings till the skin splits down the back, and the perfect cicada emerges. The dry brown pupal shells firmly attached by the sharp claws remain long after the inmates have departed.