CICADELLINA. 531 



veins, costal, median and submedian, are usually each di- 

 vided but once. 



The genus Psylla has the bristle-shaped antenuie as long as 

 the body, and a distinct pterostigma. The species are very 

 numerous, many kinds of trees having their peculiar leaf-hop- 

 per, but scarcely any have been yet described. Psylla 2^1/ ri is 

 brownish orange, with a greenish abdomen. It is very iujiu'i- 

 ous to the pear tree. 



In Livia the antennae are shorter than the bodj^, with a very 

 large and thick basal joint, and flattened eyes. Livia vernalis 

 Fitch is bright ferruginous ; the breast and tips of the antennae 

 are black, while the legs are pale rust-red. It is .15 of an inch 

 in length, and is found in vessels of sap of the sugar maple, 

 according to Dr. Fitch. 



Cercopid^ Leach. The true Leaf - hoppers possess a 

 broad, triangular head obtusely pointed in front, with a large 

 triangular scutellum not concealed by the wings when at rest, 

 and the ocelli are either two in number or entirely wanting. 

 The short, two-jointed antennae end in a bristle, being inserted 

 on the upper edge of the front, just before the eyes. The large 

 prothorax is broad and flattened and transversely oblong. The 

 fore wings are thickened, and the hind legs are long, being 

 fitted for leaping. 



Many species inhabiting grasses, such as Helochara and 

 Aphrophora, while in the larva state suck the sap of grasses 

 and emit a great quantity of froth, or in some cases a clear 

 liquid, which in the former case envelops the body, and thus 

 conceals it from sight. It is then vulgarly called "toad's 

 spittle." In Typhlocyba, which comprises many small species, 

 there are two ocelli ; the scutellum is rounded, and the front is 

 slightly concave. The species of this and the following genera 

 by their attacks on various vines and fruit trees often "kill 

 them. They are among the greatest posts of gardeners. The 

 injury is produced by their beaks in feeding, and by the ovi- 

 positor in puncturing the leaves, in which they lay their eggs. 



In Erythronenra the he:ul is crescentifonn, about as broad 

 as the thorax, with the vertex rounded down to the front, with- 

 out an angular edge ; the ocelli are situated between the vertex 



