1042 FAMILY XXXVIII. — BELOSTOMATID^E. 



About 12 genera and 60 species of Belostomatidse are known, 

 mostly from the tropical regions. Of these four genera and 20 

 species are recorded from North America, three genera and 

 seven species being definitely known from the eastern states. 

 The principal literature treating of our forms is by Say, 1832 ; 

 Leidy, 1847; Mayr, 1852, 1871; Uhler, 1884 ; Montandon, 1896; 

 Champion, 1901; Bueno, 1906a, 1923; Needham, 1907, and 

 Hungerford, 1920. 



KEY TO EASTERN GENERA OF BELOSTOMATIDSE. 



a. Fore femora not grooved in front; length, 50 or more mm. 



I. Benacus, p. 1042. 

 act. Fore femora grooved in front. 



b. Elongate-oval; cheeks meeting in front of tylus; beak elongate- 

 conical or subulate, its first joint shorter than second; larger, 

 length, 40 or more mm. II. Lethocerus, p. 1043. 



bb. Broadly oval; cheeks not meeting in front of tylus; beak subcylin- 

 drical, acute, its first joint longer than second; smaller, length, 

 less than 30 mm. III. Belostoma, p. 1045. 



I. Benacus Stal, 1862a, 205. 



This genus contains but a single species, our largest repre- 

 sentative of the family. It has the front legs more slender than 

 in the species of Lethocerus and their femora, instead of being 

 grooved in front are rounded off and widely clothed with a very 

 short velvety pile. 



1181 (1387). Benacus griseus (Say), 1832, 37; I, 365. 



Elongate-oval. Above dark olive- or grayish-brown ; head except 

 eyes, a vague median stripe and some irregular blotches on pronotum, 

 and the narrow side margins of pronotum and elytra, dull yellow; sterna 

 also dull yellow with three narrow blackish stripes ; remainder of under 

 surface and legs, fuscous-brown, the femora and keel of abdomen often 

 wholly or in part paler. Tylus short, oval, enclosed by the short broadly 

 triangular cheeks. Pronotum with a narrow median impressed line, its 

 side margins straight, converging from base to apex. Length, 55 — 65 

 mm. ; width, 18 — 22 mm. 



Lake, Kosciusko, Blackford and Marion counties, Ind., May 

 — October ; doubtless occurs throughout the State. Braden- 

 town and Istokpoga, Fla., January — March. Recorded also 

 from Clearwater, Ft. Myers and St. Augustine, Fla. Occurs in 

 sluggish waters of ponds and streams and in early summer, 

 during the mating season, often at electric lights. At that sea- 

 son numerous specimens may often be found in the washup of 

 Lake Michigan and the larger lakes of Indiana. Its known 

 range extends from Quebec and New England west to Min- 



