HUNGERFORD: AQUATIC HEMIPTERA. 205 
less than width. The interocular space behind and its width, including 
the eyes, is very much less than half of the ver large pronotum. 
‘E_ytra clear brownish, a little darker on the middle of the disc. A 
small yellowish point on the middle of the posterior border of the elytra. 
Embolium yellow in all its width on the basal *%4, brown at the extremity; 
elytral margin behind the embolium imperceptibly s.nuate, commissure 
of clavus a half shorter than the length of the scutelium; connexivum 
yellowish, hardly and very narrowly browned in the sutures of the seg- 
ments, with the posterior angles little prominent behind. Length, 7.7 
mm. to 8 mm.; width, 4.8 to 5.2 mm. Mexico, Wyoming, California.” 
Ambrysus heidemanni Montd. 
Montandon, Bul. Soc. Sci. Bucarest, 1910, XVIII, p. 188. 
“Species very close as to form, mode of construction and design to 
A. mormon Montand, differing from it only in the size, a little more 
feeble. 8.6 to 10 mm.; in the lateral sides of the pronotum less dilated and 
less strongly arcuate without, as well as the dilation of the embolium a 
little less pronounced, the spines of the posterior angles of the seg- 
ments of the connexivum a little less strong and less projecting although 
always plainly visible, and in its deeper color, in design identical but 
more extended, sometimes nearly black on the head and pronotum; the 
scutellum and corium uniformly more or less deenly brown. with the mar- 
gin of the embolium quite largely pale, poorly limited on its inner edge, 
the basai angles and the apex of the scutellum pale; the segments of the 
een marked by a transverse black band covering up their basal 
thirds. 
“The longitudinal median b'ack tand of the head quite enlarged, not 
reaching clear to the anterior border, but behind, it sometimes extends on 
all of the posterior part of the head from one eye to the other on a level 
with the posterior angles of the eyes. 
“Yellowstone Park in the puddles of water of the geysers. It is to 
the kindness of Mr. Otto Heideman, the learned American Hemipterolo- 
gist, that I owe this species which has enriched my collection. I have 
also found a very dark specimen from the same locality in the material 
of the National Museum at Washington. 
“The darker posterior part of the vertex is more often marked by a 
median yellowish spot. The black blotches of the pronotum frequent'y 
form two more or less triangular figures on each side, these very unequal 
figures sometimes united, sometimes very vague, with only the contours 
indicated in places, but recalling always the same design as in A. mormon 
Montand., and always much !ess emphasized with deeper color. 
eee ee ee 
“The margins of the pronotum as also the posterior border alwavs 
clear, the latter quite straight. and marked sometimes by irregular black- 
_ ish spots.” Taken in Wyoming. 
Genus PELOCORIS, Stal. 1876. 
Stal, Enum. Hemip., V, pp. 142-144. 
These bugs do not have the head so deeply set into the prothorax 
as the members of Ambrysus. Beak is very short. Posterior tarsi 
shorter than posterior titie. The latter outside and inside equally broad. 
Inferior side narrow, scarcely oblique. Eyes converging anteriorly, 
inner margin distinctly sinuated. Anterior angles of pronotum extending 
to the middle of the eres. 
KEY TO SPECIES OF PELOCORIS. 
A. Ventral plate of the female genital seement “cleft” or emarginate 
at tip. Prothorax stout, densely punctate. (Length, 8.2 to 9.6 mm.). 
P. carolinensis. 
