2 HEMIPTERA-HOMOPTERA. 
The headquarters of the family appear to be in Central and Tropical South America; 
a considerable number, however, are found in the Southern and Central parts of the 
United States of North America. | oe | 
In his “Synopsis of the Subfamilies and “Genera of the Membracide of North 
America” (Trans. Amer. Ent. Soc. xix. pp. 253-260), Dr. Goding enumerates sixty- 
five genera, of which the great majority also occur in Central America; a certain 
proportion also occur in Africa, Tropical Asia, and Australia; Staél (Hem. Afr. iv. 
pp. 82 et seg.) enumerates eleven genera and twenty-five species from Africa, and twenty- 
three genera as from Africa, Asia, and Australia combined ; only three genera and 
five species are recorded as European, two or three of which appear to be somewhat 
doubtful. 
The Membracide contain some of the most extraordinary forms that are found 
among the Insecta. The characters of the genera, however, are sometimes obscure, as 
they lead very closely one into the other, and it is hard to draw the line anywhere, 
although the extremes (as e.g. Membracis and Bolbonota) appear to be quite unlike 
in every way until examined with the whole series; the venation of the tegmina affords 
good characters, but is not of equal importance in all the groups, and occasionally 
breaks down. It is probable that good characters may eventually be found in the 
male organs in certain genera; but, except in one or two cases, I have found them of 
very little practical value as yet, and this will be the case until more material for 
dissection is provided. 
I am much indebted to Mons. Severin, Herr Handlirsch and Dr. Ganglbauer, and 
Dr. Aurivillius, for their kindness in sending me typical specimens for examination 
from the Brussels, Vienna, and Stockholm Museums respectively ; and also to Dr. Goding 
for his kindness in comparing many genera and species with those in his extensive 
collections and for giving me his opinion regarding them. ; 
The Membracide may be divided, for convenience’ sake, into the subfamilies mentioned 
below ; they might, perhaps, more correctly be divided into two subfamilies only, the 
Membracine and the Centrotine, but as the present state of our knowledge of the 
Homoptera generally is very incomplete, it does not much matter which arrangement 
we adopt. In the Centrotinz certain genera have the posterior process of the thorax 
wanting, but in these the metopidium is more or less strongly declivous, except in the 
ease of Athalion: the position of this genus, however, is open to much doubt, but I 
have, with much hesitation, allowed it to remain with the Membracide; it must at 
any rate be granted that its affinities are in several points strongly towards the family, 
and that certain of its species have the metopidium much more declivous than others; 
it must always, however, be regarded as holding an exceptional position. 
