THE WHERRYMEN OR WATER STRIDERS. 977 



sissippi. Very close to marginatus, but distinguished by the pale 

 marking at base of elytra, the silvery edge of front lobe of 

 pronotum and the narrower median emargination of male 

 genital. Not taken but doubtless occurs in northern Indiana, 

 as in Berrien Co., Mich., Hussey found it : "The most abundant 

 Gerris, with the possible exception of G. remigis, on all the wood- 

 land pools." 



1115 (1290). Gerris canaliculars Say, 1832, 36; I, 363. 



Elongate, slender, subparallel. Above dark chestnut-brown; front 

 lobe of pronotum with median line and narrow edge of side margins dull 

 yellow; antennae reddish-brown, darker toward tips, the incisures pale; 

 beak, legs and under surface pale brownish-yellow, often with a dusky 

 tinge, the tarsi and tip of beak darker. Antenna? and middle and hind 

 legs very slender, the former with joints 1 and 4 subequal in length, 2 

 and 3 also subequal, each about three-fifths the length of 1. Pronotum 

 elongate, narrow, its median carina evident but feeble; disk granulate- 

 punctate with hind margin narrowly rounded. Elytra usually entire, 

 reaching almost to tip of abdomen. Median groove of under surface 

 extending onto metasternum. Length, 9.5 — 10.5 mm. 



Dunedin, Fla., Nov. 23 — March 2 ; a dozen or more specimens 

 taken from a small pond in the pine woods and a ditch in dense 

 hammock ; both adults and nymphs on the former date. Raleigh, 

 N. Car., March — November (Brimley). Staten Island, N. Y., 

 Aug. 19 (Davis) . Recorded from Florida heretofore only from 

 St. Augustine, Titusville and Daytona in the northern third of 

 the State. Ranges from New England and New York west to 

 Ohio and southwest to Georgia and Florida. It is the most 

 slender-bodied of the genus, easily known by the pale under 

 surface with long median groove, and long acute spines of sixth 

 ventral. Bueno says that in New England it frequents secluded 

 little coves and bays of ponds. In his key (1923, 659) he places 

 this species with those having the antennae "not extending 

 beyond the thorax," whereas they reach to or beyond the sec- 

 ond dorsal. The three Staten Island specimens at hand are 

 wingless. 



1116 (1291). Gerris rufoscutellatus Latreille, 1807, 134. 



Elongate, sides subparallel. Head and front lobe of pronotum in 

 great part fuscous-black; remainder of upper surface, antenna?, beak and 

 middle and hind tibia? and tarsi, russet-brown; front legs, prosternum, 

 coxa? and middle and hind femora, pale brownish-yellow; sides of meso- 

 and metasterna blackish, with a silvery-gray lustre; abdomen dull yellow 

 with interrupted brownish stripes. Joint 1 of antenna? about as long as 

 2 and 3 united, 2 and 4 subequal, 3 slightly shorter. Disk of pronotum 



