-GERRIS.. 0 149 
Found in some numbers at Amula and at the Rio Sucio. Allied to G. flavolineatus's 
but differing from it in the carinate venter, the long first genital segment in the male, 
the subangularly dilated anterior femora in this sex, &c. In the apterous form the 
pronotum extends backwards over the front of the mesonotum, and the mesonotum is 
frequently raised or tumid posteriorly. The under surface is usually entirely pale. An 
apterous male from Irazu and an apterous female from Amula are figured. 
5. Gerris flavolineatus, n. sp. (Tab. IX. figg. 13,.¢; 18a, body from 
beneath, ¢; 14, 15, 2.) 
Aulasternum lineola, Sign. in litt. 
Winged form. Broad and robust (Q), much smaller and narrower(¢); above black or brownish-black, a 
curved transverse fascia at the base of the head and a narrow median vitta on the anterior lobe of the 
pronotum ochraceous; the posterior lobe of the pronotum, and usually the anterior lobe at the sides, and 
the sides of the head before the eyes, ochraceo-ferruginous ; the dorsum of the abdomen usually more 
or less ferruginous in the middle; the coxe, the rostrum, except at the tip, the connexival margins, and 
the under surface of the body ochraceous, the mesosternum with an oblique black stripe on each side 
extending backwards from the anterior coxe, the middle of the metasternum, and sometimes the sides or 
middle of the venter, blackish or infuscate ; the elytra brown, with darker nervures ; the antenne blackish 
or obscure ferruginous; the legs fuscous or brownish, the anterior femora ochraceous at the base and 
more or less marked with black above; the upper surface with very short, fine, golden pubescence, the 
lower surface thickly clothed with whitish or silvery pubescence, the ante-coxal pieces of the meso- and 
metapleura each with a silvery-pubescent spot or stripe, the pro- and mesopleura with a silvery-pubescent 
stripe. Antenne reaching to a little beyond the tip of the pronotum, rather slender, joints 2-4 subequal 
in length, 1 about one-third longer than 2. Pronotum with the anterior lobe short and somewhat sharply 
demarcated, depressed along the middle; the posterior lobe rounded behind, flattened along the hind 
margin, transversely raised between the tumid shoulders, and carinate down the middle of the anterior 
half. Elytra extending far beyond the abdomen. Mesopleura in the female strongly dilated before the 
laterally prominent intermediate coxe, narrower in the male. Abdomen short, not more than one-half 
the length of the thorax in the male, broad in the female; sixth connexival segment unarmed at the 
apex; two short genital segments visible from above in both sexes; the venter neither grooved nor 
carinate. Posterior legs with the femora about one-fourth longer than the tibia and tarsus united, the first: 
joint of the tarsi twice as long as the second. 
Var. The posterior lobe of the pronotum black, the hind margin excepted; the black markings of the under 
surface more extended. 
Apterous form. Pronotum short, not extending backwards over the mesonotum; the latter with a median line 
or vitta and a small spot on each side ochraceous, the lateral spot sometimes extended and forming a 
marginal stripe, in some specimens (¢ ) with the anterior half ochraceous or ferruginous, a black line on 
each side excepted. 
dg. Anterior femora stout, strongly curved at the base, hollowed beneath ; sixth ventral segment subangularly 
emarginate at the apex. 
Q@. Anterior femora very feebly curved at the base and less thickened. 
Length 53-93, breadth 2-34 millim. 
Hab. Mexico (Sallé, in Mus. Holm.; Mus. Roy. Belg.; Mus. Vind. Ces., ex coll. 
Signoret), Puebla, Cuernavaca, Tacubaya (Bilimek, in Mus. Vind. Ces.) ; GUATEMALA, 
Guatemala city, San Gerénimo (Champion). | 
Found in plenty in all its forms at San Gerénimo, and apparently not uncommon in 
.Mexico. The variety is represented by a discoloured winged male specimen from 
