THE WATER-BOATMEN. 1069 



gg. Palse of male with apex obliquely produced, not decurved, the 



rows of pegs in a straight line (fig. 215, h) ; pale cross lines 



of pronotum not confluent. 1211. obliqua. 



/'/. Pronotum strongly rastrate, crossed by about eight dark bands. 



1212. LOBATA. 

 ee. Pale bands of corium behind apex of commissure forming trans- 

 verse parallel series; width of vertex at base but about one- 

 fifth less than width of eye. 1213. vulgaris. 

 bb. Pale lineations of elytra tending to coalesce into a solid color or 

 longitudinal rows (pi. XII, fig. 4) ; length, 8 — 9 mm. 

 h. Membrane with regular lineations or vermicular markings like 

 those of corium (fig. 4). 

 i. Pronotum with four or five indefinite dark bands ; pegs 36 in a 

 single curved interrupted row (fig. 10) ; surface strongly rast- 

 rate. 1214. ORNATA. 

 it. Pronotum with eight dark bands; pegs 37, in an entire row, the 

 apical 12 — 14 about three times as long as the basal ones; sur- 

 face less rastrate. 1215. decorata. 

 hh. Membrane with obscure or no lineations (pi. XII, figs. 2 and 3) ; 

 pegs not over 30. 

 j. Hind angle of corium without a V-shaped yellow band. 

 k. Sides of body parallel; lineations coalescent, the corium black, 

 its margin yellow (fig. 2) ; pegs 29 — 30 (fig. 7). 



1216. KENNICOTTII. 



kk. Body broadest behind middle; corium blackish at inner apical 

 angle, its outer margins and embolium pale (fig. 3) ; pronotum 

 strongly rastrate and with 7 or 8 very narrow black lines ; 

 pegs 22 (fig. 9). 1217. lucida. 



jj. Hind angle of corium conspicuously bordered by a V-shaped yel- 

 low band; palse oblong-cultrate; pegs 27, crowded toward apex. 



1218. DUBIA. 



aa. Pronotum with 12 or 13 narrow transverse yellowish lines and with 



a percurrent median carina. 1219. convexa. 



1208 (1437). Arctocorixa interrupta (Say), 1825, 328; II, 250. 



Oblong, subparallel, robust for the genus. Above fuscous-brown, 

 darker in males ; pi'onotum with hind margin obtuse-angled ; disk with 

 about ten narrow black transverse lines, the three or four median ones 

 usually interrupted or branched; elytra with very numerous zigzag 

 similar lines, those on apical half less irregular than in obliqua and 

 lobata ; legs and front of head pale dull greenish-yellow; costal margin 

 blackish at base and again at apical third ; prosternum blackish ; meso- 

 and metapleura, and often in part the abdomen, fuscous or tinged with 

 dusky. Pronotum and elytra finely and vaguely rastrate. Male with 

 frontal impression large-oval, the narrow end below; pala as in key and 

 pi. XII, fig. 5; widely grooved on outer side, fringed on lower edge with 

 numerous long bristle-like hairs. Length, 10 — 11 mm. 



Frequent throughout Indiana, April — November, especially 

 so in spring-fed ponds and pools of streams. Ranges from New 



