THE WATER-BOATMEN. 1065 



or water-weeds. The cross-barred markings of the tegmina, 

 characteristic of nearly every representative of the family, 

 are doubtless of great value in aiding the insect to escape ob- 

 servation, on account of the consequent resemblance to the 

 debris to which they cling." 



About 50 species, representing seven genera, have been de- 

 scribed from the eastern states. On account of their close 

 resemblance their classification is very difficult, there being no 

 satisfactory keys to species extant. The principal available 

 literature treating of them is by Uhler, 1884 ; Champion, 1901 ; 

 Kirkaldy, 1908 ; Hungerford, 1917d, 1920, 1925a; Abbott, 1912, 

 1912a, 1913, 1913a, 1915, 1916, 1923, and Bare, 1925. 



KEY TO EASTERN GENERA OF CORIXID.E. 



a. Front tibiae not produced over the base of palae in the form of a 

 spur; asymmetry of male ventrals (except in Callicorixa and 

 Arctocorixa edulis) on the right side. 

 b. Inner wings present and functional. 

 c. Strigil absent. 



d. Stridular area on front femur present; hind tarsi usually marked 



conspicuously with black; palae of male with pegs in two rows 



(ng. I6 ,ll4 a). I. Callicorixa, p. 1066. 



dd. Stridular area absent; hind tarsi not marked with black; palae 



without pegs ; pronotum dark olive-green without transverse 



stripes. II. Cymatia, p. 1066. 



c c. Strigil present, on the right side ; tegmina without short black 



hairs ; pegs of palae in a single, often irregular row. 



e. Upper surface of male palae deeply incised near middle so as to 



be almost cut into two parts (fig. 215, c) ; strigil very minute; 

 head of male distinctly acuminate (fig. 215, d) . 



III. Ramphocorixa, p. 1067. 

 ee. Upper surface of palae without deep incisures; strigil larger, dis- 

 tinct; head of male rounded. 

 /. Pronotum transversely lineate, usually rastrate; tegmina more 

 or less rastrate. IV. Arctocorixa, p. 1068. 



/'/. Pronotum without lineations, not rastrate; elytra smooth, 

 polished; color, in the only known species, brownish-yellow or 

 pale reddish-brown, base of clavus and a large spot near apex 

 of corium blackish. V. Hesperocorixa, p. 1081. 



bb. Inner wings absent or rudimentary; head with hind angles pro- 

 longed, prominent; palae with pegs in one interrupted row, or in 

 two rows (pi. XII, fig. 19; fig. 215, ;'). VI. Palmacorixa, p. 1082. 

 ua. Front tibiae of males produced over the base of palae in the form of 

 a blunt spur (fig. 18) ; asymmetry and strigil on the left; surface 

 of pronotum and elytra usually smooth and shining. 



VII. Corixa, p. 1083. 



104 a The figures cited in key and text of this family (with the exception of tig. 

 21.") refer to those on plate XII, p. 1064. 



