H. M. PAKSHLEY 
W) 
111 closingi: this introduction I would express iny thanks to the 
many who have assisted in one way or another; on all sides I 
have fouiul a most hearty spirit of cooperation. It is my pleas- 
ant duty to mention especially my indebtedness to Dr. E. Berg- 
roth, of Finland, who has sent to me type specimens of his spe- 
cies, in some cases uniciues, and who has given me valuable advice; 
to Air. E. P. \'an Duzee, of California, who bravely entrusted 
to the post a large number of indispensalde types; to Air. G. C. 
C'hampion and Air. K. G. Blair for assistance in connection with 
the Walkerian species; to Air. G. A. Aloore for an extremely 
careful examination and report on the ty])e of hiteolus Fyles. 
This pajier is dedicated to my wife, who has been of great 
help in many ways, especially in translating works written in the 
Swedish language. 
Systematic Treatment 
In the following pages vill be found full descriptions of the 
American species of Aradus, with detailed distributional records, 
and figures' illustrating important structural features so clearly 
that certain jioints, such, for instance, as the shape of the an- 
tennal segments, structure of the female genital plates, and form 
of the pronotum have been entirely eliminated from the descrip- 
tive })aragTaphs. The characters of specific importance, which 
for tlie most part were first lirought forward as such in the writ- 
ings of Reuter and Bergroth, will be readily appreciated by 
students having a general knovdedge of entomological termin- 
ology; but special mention may be given a fcnv which arc less 
commonly met \vith outside the group under consideration. The 
head is peculiar in having a greatly enlarged tylus, sometimes 
called the median lolie or anterior prolongation; the ^Yidth of the 
head is always considered to include the eyes; on the vertex, 
between the eyes, are two depressions, often connected posteri- 
orly, referred to as impressions of vertex; lateral to the anterior 
ends of these impressions and oblicpiely anterior to the eyes 
are the preocular tuliercles, which have sometimes been called 
ante-, inter-, or intraocular; behind the eyes are the postocular 
tuliercles, called by some authors temporal teeth or tubercles. 
The disc of the pronotum bears six longitudinal ridges, the cari- 
nae; of these the median pair are closely approximated, the 
TH.\NS. .\M. ENT. SOC., XLVII. 
