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MEMBRA Cl DA?. 
Sub-family : CENTROTIDM. 
The modern writers on the Membracidse are few in number, and of these we may 
mention the names of Fairmaire, Walker, Stal, Butler, Goding, and Fowler, all of 
whom have proposed systems of classification based chiefly on the prouotal or alary 
characters. 
Here the onerous task of describing the Centrotidse of the world is not attempted, 
indeed the time has not arrived for such. The object of this monograph has been 
chiefly to illustrate by figures such examples of genera and species as appear to be 
characteristic. 
Such a treatment must necessarily leave many gaps in the series, partly caused 
by the difficulties to be faced in comparing the contents of distant museums, and the 
reluctance shown in some instances to lend specimens for illustration. The number 
of named species is large, but of these many are inadequately described. 
The Centrotidse may be generally recognised by having a distinct and more or 
less uncovered scutellum, and with the pronotum showing a long posterior horn or 
process which extends backwards. 
Borne genera are nevertheless destitute of this posterior horn, which makes their 
position in the family rather doubtful, and there are also uncertainties connected 
apparently with sex, as to the development of the suprahumeral processes. 
The sub-family constitutes the larger part of the Membracidse of the Old World 
continents, including Australia; but Canon Fowler has described forty species in the 
Biologia of Central America, and he separates them into twenty-four genera. Some 
of these are also represented by African and Asiatic species, but these are not identical 
with those of America. 
Latterly doubt has been cast as to the propriety of separating the Centrotidse from 
the rest of the Membracidse. Such a division has a convenience even though it may 
not prove to be quite natural. In fact the groups run into one another, and there is 
no sharp separation. Thus the genera of the Old and the New Worlds overlap, as 
may be seen in Pterygia. 
Although an attempt has been made to construct dichotomous tables of genera, it 
is well to look more to the diagnosis of species than to rely unduly on such tables, 
which are meant to be directive rather than final in their character. 
It has been said that simplicity is one of the distinctive characters of verity, and 
doubtless the idea of oneness has its charm; but if we apply it to biology, the 
