972 FAMILY XXXI. — GERRID,£. 



(Id. Antennae half or more the length of body, reaching at least to sec- 

 ond dorsal; sixth ventral of male with a single broadly rounded 

 concavity, its spines long, slender, acute, reaching to or slightly 

 beyond apex of genital; under surface of body in great part pale. 

 ;'. Front lobe of pronotum without a distinct black spot each side of 

 a pale median line; length less than 11 mm. 



1115. CANALICULARS. 



jj. Front lobe of pronotum with a distinct black spot each side of a 

 paler median line; length, 13 or more mm. 



1116. RUFOSCUTELLATUS. 



Fig. 1H4. Ventral views of male Genitalia of Gerris. o, G. argenticollis 

 Harsh. ; b, <:. marginatus Say; c, G. buaioi Kirk. (After Parshley). 



1106 (1283). Gerris remigis Say, 1832, 35; I, 362. 



Elongate-oval, rather stout-bodied. Above dark brown, the pronotum 

 sometimes in part reddish-brown, reflexed sides of abdomen reddish- 

 brown, the incisures slightly paler; base of beak, prosternum, coxae and 

 middle and hind femora dull brownish-yellow; remainder of lower sur- 

 face, antennae, tibiae and tarsi pale to dark brown, the sides of pleura 

 usually clothed with a very fine silvery-gray pubescence. Joint 1 of 

 antennae nearly as long as 2 — 4 united, these subequal in length. Disk 

 of front lobe of pronotum concave at base ; hind one three times as long, 

 finely transversely rugose, its hind portion regularly rounded without 

 depressed sides as in marginatus. Hind margin of sixth ventral of male 

 with a rounded median concavity, its spines short and stout reaching 

 nearly to tip of first genital. Length, 14 — 16 mm. 



Common throughout Indiana ; occurring probably on every 

 pond and lake and on the quiet pools of all streams. Hibernates 

 beneath logs and rubbish near their banks and sometimes seen 

 on the water on warm days in February. Ranges from Labrador 

 across the continent to the Pacific and south to Georgia, Texas, 

 Mexico and Central America. Not as yet recorded from 

 Florida, but probably occurs in its northern counties. In In- 

 diana this wherryman abounds on the shaded pools of the 

 smaller streams, and in times of summer and autumn drouths 

 it collects by scores beneath flat rocks and other cover in their 

 beds. There they remain until the water of the stream is re- 

 plenished. If not too far distant some in time find their way 

 to other pools, but if the drought is of long duration many 



