29 (June, 
ON CERTAIN BRITISH HEMIPTERA-HOMOPTERA. 
BY JOHN SCOTT. 
Revision of the Family Drnpuacrps, and descriptions of several new 
species of the Genus Delphax of authors. 
As the Vol. on the Hemiptera- Homoptera by Mr. Douglas and myself 
will not make its appearance for some little time, I have thought that 
probably it might be of assistance to those who are at work on these 
insects, if the results of our labours in certain groups down to the 
present time were laid before them as a kind of guide as I know well 
from experience how very difficult it is to determine any of the species, 
both through the indefinite manner in which they have been described, 
and their great similarity of facies. I think, however, that I have 
mastered the difficulties, and that the division of the genus Delphax of 
authors into sections, and the diagnostic characters following hereafter, 
will enable any one, after a little practice, to separate the species. The 
greater portion of the species composing this genus are of minute 
dimensions, and, by far the largest number occur only in an un- 
developed form. This may probably have led earlier collectors to 
regard them only as “immaturities,” and so they were passed over. 
Boheman was the first to do anything with these half-winged creatures, 
and, moreover, discovered that the developed and undeveloped forms of 
each species were very dissimilar, and that the outline of the genital 
segment of the male of each was different in shape (in mentioning the 
genital segment it is always to be understood that I refer to the ter- 
minal one) and Dr. Flor, acting on this hint in his Rhyncoten Livlands, 
vol. 1, describes, as well as can be done in words, the peculiarity of the 
form of the genital segment of every species known to him, both when 
viewed from the side and posteriorly. Still later, and with a greater 
depth of sagacity, Dr. Fieber observed that, in addition to this peculia- 
rity of shape, the males of this same genus had certain styloid pro- 
cesses attached to the genital segment, and visible with the aid of a 
lens when viewed from behind (these processes are situate, and diverge 
more or less from, a little above the middle of the lower margin), and 
that each species had a form of process peculiar to itself. Since then, 
he has applied the same principle to the Deltocephali, and with a like 
result. Whether this peculiarity of structure in the males holds good 
throughout the whole of the Homoptera, or is only observable in certain 
sections, is to me as yet unknown, as I have only been able at present 
to investigate the species hereafter enumerated, and those of the genera 
Civius and Deltocephalus ; but I shall feel surprised if it is not the 
general rule. 
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