228 THE CAUSES WHICH PROPAGATE 



song a second immediately began, and after he had concluded 

 another began, and so on." 



Our European species similarly behave. Near Turin I noticed 

 Plebeja and Hcematodes to congregate in the vicinity of a water- 

 wheel, on the same knoll, at a spot along an avenue, as likewise 

 the partiality of the latter for the Bull-frogs of the Po, to whose 

 " Cro-ak ! cro-ak ! crek ! crek ! " it invariably responded. As 

 regards artificial sounds, carriage-bells evoke snatches of recital 

 from Pleheja, Hamatodes, and Orni, even after the expiration of 

 their diurnal period of activity; and Solier, indeed, quotes an 

 apothecary at Aix, in Provence, to the effect that a vocalising 

 male of Orni may be induced to descend from its arcanum by 

 whistling so as to command its notes. These three ordinary 

 European Cicadse likewise change position, and show tendency to 

 migration, the distributive sequence of rivalry. As regards the 

 incentive of love, amorous modulation can, I believe, be discrimi- 

 nated m the recital of Orni, who will at times measure out his 

 notes without blending them — "Tip-a-tip! tip! tip!^^ — and one 

 day I came on two on boughs adjacent, one performing, " Derde ! 

 derde ! '' and the other, " Tip ! tip ! tip ! " Then, at the com- 

 mencement of July, when the three species are sounding on the 

 acacias and vines, I have observed the females of Orni and Plebeja 

 to fly to the vocal trellis. Fear, likewise, is expressed in the 

 music of the Cicadidae. The males of Hamatodes screak loud and 

 bird-like when shaken on the bough, when chased through the 

 air, or when beneath the bill and talons of an insectivorous bird, 

 as when held in the hand ; at this juncture, the tymbals, in lieu of 

 their wonted tremor, forcibly oscillate between convex and con- 

 cave, as Goureau has already noticed ; and the paroxysm is 

 marked by sharp solitary cries, " Wee ! wee ! " The male 

 of Orni, startled from a tree-trunk, utters similar querulous 

 notes as he flies ; those of Plebeja, in captivity, become a 

 canine snarl. 



Cicadse, as intimated, dwell on shrubs and trees. The female 

 has an auger-like ovipositor, and arranges her ova in punctures 

 made in the branches of trees. The isomorphous larvse are 

 white, with six feet ; and on quitting their sylvan nurseries 

 make their way underground by means of their strong and 

 dentated thighs, where they gnaw the roots of plants. They 



