I08 BROOKLYN MUSEUM SCIENCE BULLETIN 3. 3. 
cavities; last dorsal segment truncate at apex or feebly emarginate; 
last ventral segment as usual slightly depressed at middle of apex. 
Female: Posterior femora reaching the apex of third ventral seg- 
ment ; intercoxal process about half of the width of the cavities or nearly 
so; last dorsal segment broadly rounded at apex; last ventral segment 
somewhat sub-triangular. 
Manitoba: Selkirk (Wallis) ; Winnipeg (Wallis). 
Ontario: Toronto, E. Ontario (Entomol. Branch). 
Quebec: Rigaud (ex Liebeck) ; St. Johns Co., July (Chagnon). 
Michigan: Lake Michigan, Berrien Co., June (Hatch). 
Illinois: Palos Park, June (Liljeblad) ; Beverly Hills, May (Liljeblad); 
West Pullman, July (Wolcott). 
Indiana: Miller, May and July (Liljeblad); Pine, May and June (Wol- 
cott). 
Wisconsin: Dane Co., May (Marshall). 
Minnesota: Swan Lake, July (Mabbott, Biol. Surv.). 
Nebraska: Lincoln (Wickham). 
South Dakota: Brookings (Wickham). 
Iowa: Lake Okoboji, June (Buchanan, Biol. Surv.). 
Utah: Mouth Bear River, June (Wetmore, Biol. Surv.). 
New York: Ithaca, May and July (Cornell Univ.); June (Knight). 
New Jersey: Camden, March (Cornell Univ.). 
Pennsylvania: Essington, Delaware Co., June (Wenzel) ; Moores, June 
(Wenzel) . 
Virginia: Dyke, May (Jackson, Biol. Surv.). 
District of Columbia: Washington (Shoemaker, Davis) ; Eastern Branch, 
June (Nicolay) ; Bennings, Licking Banks, June (Wetmore, Biol. 
Surv.). 
This species has been taken on the yellow pond lily (Wenzel and 
Wolcott), on bulrushes (Liebeck) and on Sparganium (Davis). 
Donacia tuberadifrons is closely related to suhtilis and has probably 
been mixed up with the latter. It is, however, a more convex insect, 
the elytra at about apical third is less depressed above and dorsally and 
laterally more rounded, the sculpture of the intervals near apex generally 
a little coarser; the prothorax is different, more parallel, with the lateral 
tubercles and impressed median line always distinct and the antennal 
joints generally stouter. 
In the remarks following the original description I stated that the 
posterior femora reach the apex of the fourth ventral segment or beyond. 
