150 HEMIPTERA-HETEROPTERA. 
Mexico in the Signoret collection, this being labelled with the MS. name 4. lineola. 
The males of this species are constantly very much smaller than the females, and they 
have stout, curved anterior femora. The abdomen is short, with short genital segments. 
In the apterous form the pronotum is reduced to the anterior lobe, and the mesonotum 
varies in colour. The metasternum and venter are without trace of groove or carina. 
The two oblique black stripes on the mesosternum vary in length, these being greatly 
extended in the variety described. The abdomen is much shorter than in G. mexicanus. 
An apterous male and a winged female from San Gerdénimo and an apterous female 
from Mexico are figured. | 
LIMNOMETRA. 
Limnometra, Mayr, Verh. zool.-bot. Ges. Wien, xv. p. 444 (1865); Reise der Novara, Hemipt. 
p. 174, 
The two species here referred to Limnometra, Mayr, have very elongate, slender 
antenne, with an elongate apical joint, the anterior tarsal joints subequal in length, 
the head and pronotum opaque, and the pronotum (in the winged forms) subtri- 
angularly produced behind (instead of rounded, as in Gerris). The species noticed by 
Mayr are all eastern. All but one of the Central-American specimens seen are winged. 
Our two species may be separated thus :— 
Head and anterior lobe of the pronotum without black lines; pronotum 
grooved behind, the lateral and posterior margins without flavescent 
line; apical joint of the antenne very elongate . . . . . . . . opaca,n. sp. 
Head and anterior lobe of the pronotum with black lines; pronotum not 
grooved behind, the lateral and posterior margins more or less flaves- 
cent; apical joint of the antennz moderately elongate . . . . . . guadrilineata, n. sp. 
1. Limnometra opaca, n. sp. (Tab. IX. figg. 16, ¢; 16a, body from 
beneath, 3.) | 
Winged form. Rather narrow, opaque, brownish-ferruginous above, ochraceous or pale ochraceous at the sides 
and beneath ; the head with a spot in front and a streak on each side between the eyes, and the pronotum 
with a spot at the hind angles and the groove within the posterior margin, blackish-brown, the pronotum 
with a posteriorly narrowing pallid median line on the anterior lobe, bordered on each side with reddish- 
brown; the pleura streaked with reddish-brown; the elytra blackish-fuscous, with the nervures darker ; 
the wings blackish; the antenne blackish or fuscous; the legs fuscous, with the anterior femora pale 
at the base; the elytra, and the sides of the disc and the posterior groove of the pronotum, clothed with 
fine golden pubescence; the under surface and pleura with pallid pubescence, the ante-coxal pieces of the 
meso- and metapleura each with a conspicuous silvery-pubescent spot. Antenne exceedingly slender, 
reaching the tip of the elytra, joint 1 one-fourth longer than 2, 8 a little longer 1, 4 very elongate, more 
than twice as long.as 2. Pronotum. carinate down the middle, the posterior margin grooved within. 
Mesopleura moderately dilated before the intermediate coxe. Anterior tibie straight. Anterior tarsal 
joints subequal in length. Posterior legs with the femora nearly one-half longer than the tibia and 
tarsus united, the first joint of the tarsi almost twice as long as the second. Rostrum nearly reaching 
the middle of the mesosternum. Mesosternum grooved down the middle. 
6. Metasternum carinate down the middle; sixth connexival segment obtuse at the outer apical angle; sixth 
ventral segment simply arcuate-emarginate at the apex; anterior femora bowed and moderately. thickened. 
