schaeffer: donaciini of the new world. 95 
at sides and occasionally on the disk confluent; median impressed line 
absent or feeble. 
Elytra more or less shining with scarcely a trace of coarse, trans- 
verse rugae; apices truncate, exterior angles rounded; strial punctures 
large at base, becoming gradually smaller towards apex; intervals 
moderately coarsely rugose towards base, more finely near apex; lateral 
margin more or less acute; ante- and post-median impressions more or 
less distinct. 
Body beneath densely and finely punctate; pubescence cinereous, 
not very dense, permitting the metallic surface color to be seen ; pubescent 
space near anterior coxae small; intercoxal process of mesosternum 
variable in the two sexes; posterior femora extending to or beyond the 
apex of third ventral segment, distinctly clavate in more than apical 
half, at base narrower than apex; below armed in both sexes with a 
small tooth, which is occasionally indistinct or absent. Length: 6- 
7.5 mm. 
Male: Intercoxal process of mesosternum slightly narrower than 
half the width of the coxal cavities; last ventral segment distinctly 
depressed at middle of apex; last dorsal segment truncate or feebly 
emarginate at apex. 
Female : Intercoxal process of mesosternum about half as wide as 
the width of the coxal cavities. Last ventral segment gradually narrower 
towards apex, which is rather broadly rounded; last dorsal segment 
similar but sub-truncate at apex. 
Michigan: Whitehall, July (Liljeblad). 
Massachusetts: Stoughton, August (Blake) ; Southboro, June (Frost). 
New York: Saranac Lake, September (Shoemaker); West Nyack, 
August (Bequaert); Hamilton Co.; Staten Island, July (Leng). 
New Jersey: Atsion, August (Wenzel); Swartswood Lake, September 
(Nicolay). 
District of Columbia: Washington, July (McAtee). 
Virginia: Alexander Co., July (Shoemaker). 
Florida: Enterprise, May (Hubbard and Schwarz). 
Sagittaria is given as the host plant of this species by Mr. Leng and 
Pontederia cordata by Mr. Wenzel ; the latter sent me the following note : 
"Mate during the day. Found only on the host plant growing in clear 
water with a hard sand and gravel bottom, in such places the plants do 
not grow as luxurious as in a mud bottom." 
Though rather closely related to subtilis, ntgosa differs from that 
