INSECTA. 133 



rior legs susceptible of folding up so as to form a forceps ; 

 tarsi with one or two articulations ; they are all aquatic and 

 carnivorous, and sting severely. 



Section II. Homoptera. 



Beak springing from the lowest part of the head ; females 

 provided with an ovipositor, composed of three dentelated 

 laminae, which they employ in notching vegetables to deposit 

 their eggs ; elytra throughout of the same consistence, and 

 always tectiform and semi-membranous. Three remarkable 

 genera. 



GENUS I. CICADA. 



Tarsi with three articulations ; antennae of six joints ; head 

 wider than the corselet; three simple eyes; elytra not crossed, 

 tectiform, transparent and veined ; a musical instrument in 

 the males, composed of two kinds of drums or scales, which, 

 through the influence of little muscles, become alternately 

 convex and concave. 



GENUS II. APHIS. 



Tarsi with two articulations terminated by two hooks; 

 antennae with six or seven joints; elytra and wings oval or 

 triangular and tectiform ; beak very distinct. Nearly all 

 these animals live in societies upon trees and plants, whose 

 juice they suck with their proboscis. Their punctures cause 

 the leaves or young vegetable shoots to assume different 

 forms, as may be seen upon the young shoots of the linden, 

 the leaves of the gooseberry, the apple, and more especially 

 the elm, the poplar and the pistachio, where they produce 

 warts or excrescences, enclosing families of Aphides, and 

 often an abundant saccharine liquid. 



GENUS III. Coccus, Lin. 



One joint only to the tarsus, with a single hook at the end ; 

 females without wings, and provided with a beak; the males 

 have two wings, which lie one over the other horizontally ; 

 antennae filiform or setaceous, and most commonly with 

 eleven joints. The Cochineal (C. Cacti) belongs to this 

 genus. 



