schaeffer: donaciini of the new world. 47 
The sinuate sutural margin of elytra is said by Mr. Leng in his 
"Review of the Donacia of Boreal America" ^ to be present also in 
distincta but that is a mistake. The distincta of his revision, however, 
is not Leconte's species but hiimpressa Melsh. Both, the true distincta 
of Leconte and hiimpressa Melsh., have the sutural margin straight to 
apex as in the rest of the species of the subgenus Donacia. 
The species of the subgenus Plateumaris are more uniform and 
differ less in form from each other than the species of the subgenus 
Donacia and I have made several attempts to find additional characters 
which would justify the generic standing of Plateumaris but did not 
succeed in this. At one time I thought I had found these in the absence 
of a pubescent spot near the anterior coxae and the difference of the 
vaginal plates of the females of Plateumaris from those of the subgenus 
Donacia. However, in diversa, a new species of Plateumaris, there is a 
pubescent spot near the anterior coxa, though not as distinct as in most 
of the species of the subgenus Donacia. The vaginal plates in the single 
female of the European consimilis before me are sufficiently visible to 
show that they are widely different from the usual type seen in Plateu- 
maris and are more nearly like those seen in some species of the subgenus 
Donacia, that is, they are rather wide, both nearly equal in length and 
width, and broadly rounded at apex, but not narrowed triangularly into 
a sharp point. In pubicollis, a species of the subgenus Donacia, the 
lower plate, though wider than in the majority of the species of Plateu- 
maris, is distinctly triangularly converging towards apex into an acute 
point, which apparently indicates the same mode of oviposition as in 
Plateumaris. In regard to the generic difference between the larvae of 
Donacia and Plateumaris, Dr. Adam G. Boving on p. 20 of his valuable 
paper "Natural History of the Larvae of Donaciinae" - says: "Re- 
specting the classification of the larvae within the Donaciinae tribe, it 
might be anticipated that the specific, well-marked difference between 
the imagines of the Haemonia and Donacia also exists between their 
larvae. And, inversely, the fact that Thomson had only been able to 
point out feebly pronounced differences between the imagines of Donacia 
and those of the Plateumaris genus established by him might lead to 
the conjecture that it would be difficult to distinguish between the 
larvae of these two genera;^ yet, the case is entirely reverse, the Haemonia 
larvae not being distinguishable from the Donacia larvae, whereas 
Plateumaris larvae and Donacia larvae present rather numerous and 
1 Trans. Am. Ent. Soc. XVIII (1891). 
'^ Mitteilungen aus dem Siisswasserlaboratorium Fredericksdal by Lyngby, No. 
VII, 1910. 
