i62 HOMOPTERA 



SuBF. CENTROTIN/E Spinola 



The subfamily Centrotinae is the largest of all of the subfamilies of the Membracidae. It contains 

 more genera, more species, and probably more individuals than all of the other subfamilies combined. 



Apparently it is the only subfamily represented in the Old World. Occasionally a species from 

 Europe, Asia or Africa has been described and assigned to a genus in some other subfamily but in each 

 instance dissection has proven that the insect has a complete and well developed scutellum even though 

 it may be entirely hidden. The New World Centrotinae, while represented by a considerable number of 

 genera, are not nearly so conspicuous nor so abundant as are the New World species of the other sub- 

 famihes. They are usually smaller in size, less fohaceous and bizarre in appearance, and their 

 numbers must be coiiiparatively few, as they are seldom coUected and are always meagerly represented 

 in collections. 



The Centrotinae may be ver)' definitely divided into New World and Old World forms. Not a 

 single genus has yet been found which is common to both the eastern and the western hemisphere except 

 in the case of a few species which are known to have been introduced on shipments of plants. While 

 the new World and the Old World forms are undoubtedly closely related, both their natural structures 

 and the somewhat more artificial characters which are often a convenience in constructing taxonomic 

 keys, are remarkably distinct. 



Therefore it is botli natural and convenient to subdivide the Centrotinae into the two great geo- 

 graqhical groups as we are here doing in arranging the genera. Such an arrangement greatly simpH- 

 fies the identification of tribes and genera, and until and unless cosmopohtan forms are discovered, it 

 should prove entirely satisfactory. 



TRIBES OF THE NEW WORLD CENTROTINiE 



I. Pronotum withoiit a poslerior process Abelini Tribus novus. 



II. Pronoium with a posterior process 



A. Clavus gradually aaiminate from base to apex Acuminatini Goding. 



B. Margins of clavus parallel ornearly so Hebesini Goding. 



GENERA OF THE TRIBE ABELINI (TRIBUS NOVUS) 



I. Apex ofclavus obtuse and nearly truiicaie Abelus Stal. 



II. Apex of clavus acuminate 



A. Base of head not tuberculate 



i. Head triangular ; tegmina coriaceoHS Stictodepsa Stal. 



2. Head subquadrate ; tegmina hyaline Scytodepsa Stal. 



B. Base of head sulcate in middle ; tuberculate on each side 



1. Hind wiugs wilh two apical cells; pronotumunarmed Tropidaspis Stal. 



2. Hind wings wilh four apical cells 



