THE BACK-SWIMMERS. 1053 



(1905a, 163) records it from Indiana without definite locality. 

 It varies much in the black markings of the elytra, these in 

 some specimens being wholly absent. The dark hue of hind 

 part of pronotum and base of membrane is due to the black of 

 the underlying portions as seen through the subhyaline texture. 

 Bueno (loc. cit.) states that it "prefers to float in clear spaces 

 in clean cold pools about midway between the bottom and the 

 surface." 



1190 ( — ). Notonecta borealis Bueno & Hussey, 1923, 104. 



Oblong, robust, strongly tectiform. Color above a nearly uniform 

 dull yellow; scutellum paler yellow; elytra with a more or less interrupted 

 fuscous-brown submarginal stripe; under surface brownish-black, the 

 prosternum paler; legs and beak dull yellow, the tip of latter and the 

 coxa? blackish. Pronotum about two-thirds wider than long, its side 

 margins sinuate. Scutellum one-fourth wider at base than long, its 

 apex less prolonged than in irrorata. Length, 12.4 — 14.2 mm. 



Douglas Lake, Mich., July 24 (Gerhard). A boreal species 

 whose known range extends from Maine west to the Bearfoot 

 Mountains of British Columbia. Of its habits Hussey (loc. cit.) 

 says : "It was noted to rank next in abundance to A", undulata 

 at Douglas Lake, Mich., where it was the only Notonecta whose 

 adults were found commonly before July 20. Its favorite 

 haunts were the partially filled peat bogs, where it preferred 

 the open water and was only very rarely taken among vegeta- 

 tion." 



1191 (1353). Notonecta howardi Bueno, 1905a, 151. 



"Notocephalic lateral margins of head curved; vertex twice as wide 

 in front as at base. Pronotum four-fifths broader than long, humeral 

 and lateral margins sinuate. Scutellum one-fifth longer than wide, not 

 concolorous. Hemelytra clouded with black going into smoky and with a 

 broad black band across membrane and apex of corium; apex of mem- 

 brane smoky. Corium and clavus moderately clothed with a golden 

 pubescence. Membrane lobes subequal. Pedes: Intermediate femoral 

 spur, small, rather blunt, concolorous. Length, 10.2 mm." (Bueno). 



Described from Arizona. Recorded by Drake (1922a, 116) 

 from Fayette, Miss. 



1192 (1352). Notonecta undulata Say, 1832, 39; I, 368. 



Oblong, subcuneiform. Color above exceedingly variable, ranging 

 from entirely uniform dull greenish-yellow to nearly wholly black. In 

 the majority of northern examples at hand the color is very nearly that 

 of insulata as above described, with the exception that the scutellum has 

 the side margins and tip pale; in the southern individuals the scutellum 

 and elytra except clavus are usually velvety black; under surface and 



