for. -@BRRIB 0b 147 
'. patches ‘in the male ; the legs a little more slender, the anterior femora moderately stout ; sixth connexival 
segment with the outer apical angles more acute in both sexes. 
Apterous form. Pronotum formed as in G. remigis, obscure ferruginous or ochraceo-ferruginous. : 
do. Ventral segments shallowly sulcate down the middle, the sixth also transversely depressed, the latter 
broadly and deeply emarginate in the centre at the apex, with the apical margin ciliate; the genital 
segments formed as in G. remigis.. Sixth connexival segment produced at the outer apical angle into & 
long and acute spine, usually extending to the middle of the long first genital segment. 
Q. Ventral segments with only the faintest trace of an impressed median line. Sixth connexival segment 
_ With the spine less acute, ¢ curved a little inwards, and about reaching the apex of the short first genital 
- segment. 
Length 114-16, breadth 3-4 millim. 
» Hab, Nortn America®, Clear Lake, California}, Lower California ?.—MExtco (Sallé 
& Boucard, in Mus..Holm.; Bilimek, in Mus. Vind. Ces.), Monclova in Coahuila 
(Dr. Palmer), Tacubaya (Bilimek, in Mus. Vind. Ces.). 
Fourteen Mexican specimens, including winged and apterous specimens of both sexes, 
are referred to this species. They are very closely allied to G. remigis; but differ from 
it'in the form and coloration of the venter in the male, and in the more acute connexival 
spines in both sexes. The posterior portion of the pronotum is constantly ochraceo- 
ferruginous or rufescent. In the male the venter is shallowly grooved down the middle, 
and, at most, slightly infuscate on each side of the median groove. 
The original description was made from a badly mutilated female example. I have 
seen a Mexican specimen, received from Mr. C. Baker of Auburn, Alabama, which I 
believe has been determined by Prof. Uhler as G. robustus. 
The present insect somewhat resembles G. rufoscutellatus, Latr.; but it is more robust 
and less parallel, and has shorter connexival spines, &c. 
3. Gerris mexicanus, n. sp. (Tab. IX. fig. 10, 3.) 
Winged form. Moderately robust, rather elongate ; black, a transverse curved line at the base of the head and 
a median line on the anterior lobe of the pronotum ochraceous; the posterior lobe of the pronotum, except 
in the centre in front and at the sides above anteriorly, ochraceo-ferruginous or brownish-testaceous; the 
elytra brown or reddish-brown ; the coxa, the ante-coxal pieces of the meso- and metapleura, the apex of 
the abdomen beneath, the prosternum, and the rostrum, except at the tip, ochraceous; the connexival 
margins narrowly ochraceous or ferruginous; the legs brownish-ferruginous or fuscous, the anterior 
' femora ochraceous at the base and sometimes with a blackish line above; the antenne blackish, the basal 
. one or two joints usually in part ferruginous ; above somewhat thickly clothed with very short fine golden 
or greyish pubescence, the lower part of the pleura and the under surface with silvery pubescence. 
Antenn reaching to the tip of the pronotum, rather stout, joints 2-4 subequal in length, 1 about one-half 
longer than2. Pronotum with the anterior lobe short; the posterior lobe rounded behind, flattened along 
the hind margin, obsoletely carinate down the middle, tumid at the shoulders, and sometimes transversely 
— raised between them. Elytra extending beyond the abdomen in both sexes. Mesopleura strongly dilated 
before the laterally prominent intermediate coxse. Abdomen shorter than the thorax; sixth connexival 
segment unarmed at the apex; two genital segments visible from above in both sexes, the first long in 
the male and very short in the female, the second very short in the male. Metasternum and venter 
faintly carinate down the middle. Intermediate and hind legs moderately elongate. Anterior femora 
stout. Posterior tarsi with Joint 1 two and one-half times as long as 2, Posterior femora about as long 
as the tibia and tarsus united, | 
Naas 
19* 
