MEMBRACID^. 5 



remarkable periodic Cicada, Cicada septcndccim, whose 

 ravages fortunately are unknown to us in England. Prof. 

 Riley compares their noise to a compromise between 

 the distant sound of a threshing-machine and the din of 

 a croakingfrog-pond. The common note maybe imitated 

 by a pronunciation of the letters, "Phar-r-r-r-aoh," and 

 continued for perhaps three seconds. Then there is a 

 louder call, nearer to a screech, "Tsh-e-e-e-ou." This 

 is taken up, in unison, by the numerous males around, 

 and the effect is deafening. There is yet a third sound, 

 which consists of from fifteen to thirty sharp chirps, 

 which somewhat recall the notes of the chimney- 

 swallow. (See ' Science,' Sept. 25th, 1885. _ Vol. vi.) 



A remarkable point in the economy of this American 

 Cicada is the curious erect earthern tubes it constructs 

 above the ground, within which the insect undergoes 

 its transformation into the ima<:jo. 



II.- MEMBRACIDJE, Stal. 



Crown almost vertical. Ocelli two, on the crown. 

 Frons much deflexed, and nearly horizontal. Tegal« 

 wanting. Hind coxae transverse, reaching nearly to 

 the sides of the sternum. TibijB prismatic. Posterior 

 femora unarmed above. Elytra with many cells ; 

 apical cells five. 



The British known species may be divided into two 

 genera, the general characters of which may be thus 

 tabulated : — 



Centrotus. 



Head. Punctured. 



I With a horn on each side. 

 Hind process bisinuate, not 

 conceahng the scutelluin. 

 Abdomen. Black, shining, punctured. 



f Rough, fusco-hyahne, with 

 brown nerves and a fuscous 

 spot on the filth apical cell. 



"Wings. J Hyaline, with brown veins. 



Reddish yellow ; edges of 

 Tibiae. -I third pair with black 



setiferous granules. 



Gargara. 



Black, punctured, shining. 



"Without side horns. Hind 

 process straight, and 

 liiding the scutellum. 



Yellowish brown, with yel- 

 low pubescence. Nerves 

 darker. 



Membrane of the elytra 

 " grossicrement bosse- 

 lee" (Fieb.). 



Brownish. 



