MEMBRA Cl DAE. 
17 
When practicable I have given outlines of venation from the insects described, 
but I append a sketch plan to show what is meant by the nomenclature used in the 
diagnosis. 
The cubitus may be forked, and this shorter branch may be forked again, as 
seen in Membracis. The question is, should the area enclosed by the first furcation, 
bounded by the fine apical nervure, be counted as a subcubital area, or the first 
apical area ? I prefer to call it apical, and thus Membracis will have five and not 
four apicals. 
The area marked X I call the sutural area. 
Where there is no subcubital the first apical would touch the cubitus, but it is 
difficult to form a rule for all genera. 
The Wings .—A few words will suffice as to the neuration of these more simple 
organs, which are smaller than the tegmina, and are folded behind them. Usually, 
as in Umbonia, they have broad corrugated outer margins of delicate membrane. 
The base gives off from four to five radials, enclosing petiolate areas, with angular 
cross-veins connecting the first with the second, and the second with the third main veins. 
In this manner four, five, or more apicals, two discoidals, and three anal cellules 
may be formed. The variations are numerous, as shown in different species. The 
subdivisions of the membrane are not easy to describe in words, but some cellules 
may be seen drawn on the plates to follow in the diagnoses. 
The Abdomen .—In Hemiptera, and, still more, in Homoptera, there is difficulty in 
determining the exact number of the abdominal somites, or rings. This in great part 
is due, at least amongst the Homoptera, to the whole or partial overlapping of the 
mesothorax with its scutellum and the smaller metathorax below it. Again, it is not 
yet decided how many segments are theoretically comprised in the development of 
the genital apparatus of the sexes. 
The female of Membracis mexicana has clearly nine segments, the last of which 
constitutes the pygofer of Fieber and other authors. In Aconophora ten may be 
counted, whilst in Umbonia, perhaps, there are eleven somites. 
The stomata or spiracles are ranged in a row on each side of the abdomen, but they 
are not easily seen, unless the insect is bleached and mounted in Canada balsam. 
They are not protected by pleural or lateral folds as in some other Homoptera like 
Aphides, which often show them guarded by the connexivum. 
The stomata in Membracis are six in number, but probably the normal abdominal 
number should be seven, in addition to three others on the thoracic portions. 
As a rule the abdominal parts of the males are flatter and smaller than those of 
the females. The females are robust and deeply ringed, the last segments being often 
the broadest, and developing the genital valves from the under side. 
c 
