976 FAMILY XXXI. — GERRID^E. 



1112 ( — ). Gerris comatus Drake & Hottes, 1925, 48. 



Color of body, legs and antenna? as in marginatus. Elytra always 

 present but variable, reaching to first dorsal genital, or only to fifth 

 dorsal. Male with sixth dorsal deeply, broadly and roundly emarginate 

 and ending in very short spines. Ventrals of male indistinctly carinate, 

 3 — 6 somewhat depressed, hind margin of 6 deeply and roundly excavated. 

 Sixth ventral of female with terminal spines slightly shorter and more 

 obtuse, and clothed with longer hairs. Length, 7.3 — 8.2 mm. 



Ames, Iowa, July 24 (///. Nat. Hist. Sun: Coll.). The re- 

 corded range extends from Maine and New Jersey west to Wis- 

 consin, Colorado and Wyoming. 



1113 (1289). Gerris buenoi Kirkaldy, 1911, 246. 



Oblong, narrower behind, robust for the genus. Above dull fuscous- 

 black; a short median line on front lobe and narrow marginal one on 

 both front and hind lobes of pronotum and margin of connexivum both 

 above and beneath, dull yellow; antennae, tibia? and tarsi brown, their 

 terminal portions darker; prosternum, coxa?, sixth ventral, genitals, and 

 femora in great part, dull yellow, the front femora blackish above and on 

 sides. Joint 1 of antenna? subequal in length to 2 and 3 united, 3 shortest, 

 4 two-thirds the length of 1. Disk of pronotum finely and densely punc- 

 tate, the hind lobe with median carina evident, but feeble; hind margin 

 rather narrowly rounded. Elytra usually present, reaching tip of abdo- 

 men. Hind tibia? and tarsi united scarcely as long as femur. Other 

 characters as in key. Length, 7 — 8 mm. (Fig. 193). 



Staten Island, N. Y., July (Davis). South Chicago and Worth, 

 111., Sept. 14 — Oct. 9 (Gerhard). Attleboro, Mass., mating June 

 21 (Frost). Ranges from Quebec and New England west to 

 British Columbia and Colorado. Not recorded south of New 

 Jersey. Drake (1923, 80) mentions it as by far the most 

 abundant species of the smaller forms of Gerris found about 

 Cranberry Lake, N. Y., its habits and haunts being quite 

 similar to those of G. marginatus. 



1114 (1288y 2 ). Gerris argenticollis Parshley, 1916, 103. 



Form and size of G. marginatus. Color much the same, the side 

 margins of front lobe of pronotum with a yellow stripe which is clothed 

 with thick silvery pubescence; inner margins of basal third of elytra 

 usually marked with dull white or yellowish between the veins. Joint 1 

 of antenna? slightly longer than 2 and 3 united, 4 about two-thirds the 

 length of 1. Pronotum as in marginatus, the side margins of posterior 

 third of hind lobe wider and more depressed in both than in buenoi. 

 Length, 7.5 — 8.5 mm. 



Staten Island, N. Y., April (Davis). Forest Hills, Mass. 

 (Barber). Chicago, 111., April 30 (Gerhard). Ranges from New 

 England west to Michigan and Illinois and southwest to Mis- 



