Recognition of the Cicadellidae. 



It is not probable that the Cicadellidse would be confused 

 with any of the Homoptera Sternorhynchi, for in the latter, 

 among the differences, the beak seemingly arises from be- 

 tween the prothoracic legs instead of the posterior portion of 

 the head, the antennae are of any form except setaceous as they 

 are in the leaf hoppers, and the tarsi are composed of one or 

 two segments, while in the leaf hoppers there are always three. 



Of the Homoptera Auchefiorhynchi the Cicadidse, because of 

 their much larger size, need never be confused with the leaf 

 hoppers. The Fulgoridx are also distinguished from them by 

 having the variously formed antennae situated directly below 

 the eyes, instead of having the invariably setaceous antennae 

 between and below the eyes. The Membracidfe usually have the 

 pronotum extending back over the abdomen, whereas that of 

 the leaf hoppers does not. In the few tree hoppers where the 

 pronotum does not extend back over the abdomen, we do not 

 find the hind tibiae provided with the double row of stout spines 

 as in the leaf hoppers. The Cercopidas are separated from the 

 leaf hoppers by also lacking these spines, having instead one or 

 two stout spines along the tibiae and a circlet of small ones at 

 the apex. 



The following is a key for the separation of these families : 



A. Large insects with three ocelli. Cicadidse. 



AA. Smaller insects with two or no ocelli. 



B. Pronotum usually prolonged backward over abdomen; hind 

 tibiffi without double row of spines. Membracidse. 



BB. Pronotum never prolonged backward over abdomen. 

 C. Antennae setaceous, between and below eyes. 



D. Hind tibiae with distinct double rows of spines. 



Cicadellidas. 

 DD. Hind tibiae with one or two stout spines and termi- 

 nating in a circlet of small spines. Cercopidse. 



CC. Antennae of various forms but directly below the eyes. 



Fulgoridse. 



It will be seen from the above that the characteristically 

 spined hind tibiae alone are enough to distinguish the leaf hop- 

 pers from any of the other families. Indeed this is the out- 

 standing feature of the family. 



(53) 



