104 
Journal of Agricultural Research 
Vol. XXX, No. 2 
line anteriorly; compound eyes large, 
each accompanied behind by a pro¬ 
truding ocellus; legs long and slender, 
the parts cylindrical, bearing numerous 
spines or setaelike hairs, the tarsal 
claws each with 2 digitules and usually 
1 or 2 denticles near apex; wings 
rather long and slender, usually show¬ 
ing more or less whitish bloom on the 
surface, costal margin thickened, with 
1 subbasal diagonal thickening or vein 
running nearly to margin, a more or 
less distinct clear line somewhat beyond 
and paralleling this, and rarely ( prae - 
longa ) a second diagonal thickening 
intermediate in position between costal 
and basal diagonal veins, less distinctly 
developed than either and incomplete 
basally; abdomen terminating in a 
bivalved penis sheath, this curving 
back and down, with the tips of the 
valves closely appressed and forming a 
rounded conical apex, and on a single 
abdominal segment before this sheath 
with a transverse row of long tubular 
ducts, these producing the tuft of 
glassy threads to be seen in the living 
insect. 
The preceding diagnosis of the adult 
male stage has been based on males of 
only four species and in consequence 
may not be entirely accurate for all the 
members of the genus. Neither 
thoracic nor abdominal spiracles were 
to be observed in any of the specimens 
examined, although almost certainly 
present. No definite group or specific 
characters were observed in the few 
species examined, and their existence 
seems somewhat doubtful, although a 
detailed study of the more minute 
derm structures might possibly result 
in the discovery of such characters. 
One subgenus, which has also been 
regarded as a genus by some, has been 
erected within the genus Orthezia and 
appears, on the basis of the studies 
detailed here, to be valid. It may be 
separated from typical Orthezia by 
the key following. 
KEY TO SUBGENERA OF ORTHEZIA 
a. Without 3 triangular clusters of 
spines on the anterior portion of 
the dorsum along the median 
line, and the corresponding trian¬ 
gular plates of secretion also 
wanting; when fully developed, 
with 11 marginal and 10 dorsal 
pairs of clusters or bands of 
spines, and with a corresponding 
number of plates or tufts of 
secretion; eyestalk sometimes 
strongly asymmetrically conical, 
but never thumblike; tarsal claw 
with denticles. Orthezia s. str. 
aa. With 3 more or less distinct trian¬ 
gular clusters of spines on the 
anterior portion of the dorsum 
along the median line, and with 
3 distinct triangular plates of 
secretion corresponding to these; 
clusters of spines fully developed, 
forming only 10 pairs of marginal 
clusters instead of 11, the secre¬ 
tion of the perfect insect corre¬ 
sponding; eyestalk strongly pro¬ 
duced, thumblike; tarsal claw 
without denticles_ 
-Arctorthezia Cockerell. 
SUBGENUS ORTHEZIA S. STR. 
The characters of the subgenus Or¬ 
thezia s. str. have been sufficiently 
indicated in the generic diagnosis of 
the various stages and in the subgeneric 
key given above. 
At least one of the members of this 
subgenus, owing quite evidently to 
artificial dissemination, is at present 
world-wide in its distribution, although, 
as has already been indicated, the sub¬ 
genus appears to be American in origin 
and development, the majority of the 
described species coming from the 
Western and Southwestern States and 
nearly all of the remainder from tropical 
or Neotropical America. 
In the matter of host relationships 
the members of the subgenus, largely 
because of the diverse tastes of a few 
species, show so wide and varied a 
range that no precise connection be¬ 
tween'the subgenus as a unit and the 
hosts of its members is evident. 
Among the members of this subgenus 
are present some fairly evident groups 
of species, and, in addition, some spe¬ 
cies which appear to stand alone. As 
these suggested groups can not be suc¬ 
cessfully placed in any linear arrange¬ 
ment and are not indicated in the key 
to the species which follows, or in the 
arrangement of the specific descrip¬ 
tions, it seems desirable to outline 
them very briefly, with the definite 
understanding that the order of ar¬ 
rangement as given in the following 
tabulation is not intended to show any 
proper phylogenetic or other sequence. 
I. insignis Dougl. Characterized 
primarily by the complete ab¬ 
sence of transverse rows or 
bands of spines in the ventral 
abdominal region and, sec¬ 
ondarily, by the very marked 
reduction of the dorsal spine 
bands and corresponding se¬ 
cretion. 
