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Article II. — Jassidw of Illinois. Pakt I.* By Charles 



W. WOODWORTH, M. S. 



FAMILY JASSIDiE Stal. 



The insects included under the name Jassida-, form a 

 large and well-defined^natural group. They are readily distin- 

 guishable from members of the allied families as follows: from 

 Cicadidie by the possession of but two ocelli (or none) instead 

 of three, as in the latter family; from Cercopidae by having 

 broad transverse posterior coxae instead of conical 'ones, and 

 having tiie posterior tibiae prismatic instead of round; and, 

 histly, from Membracidae by having the thorax only slightly 

 convex and not strongly declivous. Aside from this there is a 

 general resemblance between forms of the same faniily, so that 

 they may be very readily distinguished at a glance; but the above 

 characters are useful chiefly for doubtful cases, before the 

 student becomes familiar with the various forms. 



By Linnajus, in his Sijstema Naturce, this family^together 

 with the above enumerated related ones was first all included 

 in the single genus Cicada, which was thus characterized: 



"Rostrum inflexed. Antennae setaceous. Wings 4, mem- 

 branous, deflexed. Feet (generally) saltatorial." 



Later, Geoffroy proposed the name Tettigouiafor those hav- 

 ing but two ocelli, reserving Cicada for those having three ocelli 

 situated on the vertex. Fabricius in his Entomolof/ia Si/stematiai, 

 1794, seems to have misunderstood Geo&oy, for he used Tetti- 

 gonia for Cicada and applied the latter name] to our^ present 

 group Jassida}, having separated from them^the Cercopida^ and 

 Membracida? as genera, giving them the names Cercopis and 



*The present article includes only the subfamily Tettigoninse. I 

 hope soon' to complete theVemaining part. 



I have.made use of 'the. collections and library of the State Labora- 

 tory of Natural History in preparing the'present paper, and wish here 

 to acknowledge the kind favors and encouragement received from the 

 Director, Prof. S. A. Forbes. 



