schaeffer: donaciini of the new world. 49 
pronounced distinct species. In some specimens the prothorax appears 
to be elongate but is at least as wide at apical margin as long, in other 
specimens of the same species it is distinctly transverse, that is, wider 
than long. The apical angles vary also a great deal and are in certain 
species from feebly distinct to more or less projecting into an acute point. 
The longitudinal median impressed line is in some species always present 
and distinct, in other species absent or feeble in some specimens, but is 
occasionally present in species which generally have no impressed median 
line. The sculpture is in some species exceedingly variable from very 
finely and sparsely punctate to coarsely and densely punctate. The 
lateral tubercle, though variable to some extent, is more constant but is in 
specimens of some species absent, which generally have a feeble tubercle. 
The lateral margin below the tubercle is usually more or less undulate, 
sinuate or almost lobate in some species and is subject to variation in 
specimens of the same species. Occasionally one more or less distinct 
fovea-like impression on each side of the median line may be present in 
a specimen of almost any species. They are generally very regular 
and are misleading as they may be considered a constant character. 
Melsheimer called one of his species hiimpressa on account of these two 
fovea-like impressions on the prothorax of his types and Dr. Leconte's 
aurifer var. of his revision was separated from the typical form by having 
two thoracic impressions. These impressions are possibly caused by 
"muscular exertion on the part of the insect while the body surface is yet 
soft" as suggested by Dr. Blaisdell in his revision of the Eleodini. 
The elytra varies a good deal in form in specimens of the same species. 
The impressions or indentations on each side of suture are variable in 
distinctness and the post-median is often faint or entirely absent. The 
sculpture is also subject to variation in the same species. 
The underside of the body and legs vary relatively little in sculpture 
and pubescence in nearly all our species with the exception of biimpressa 
Melsh. in which the pubescence and punctuation, especially of the first 
ventral segment, is very variable. The armature of the posterior femora 
is more or less constant in some species, in others it varies a good deal. 
In species with one small tooth in both sexes the tooth is occasionally 
absent or indicated by a more or less distinct angulation. The species 
with more than one femoral tooth have often the anterior one absent or 
reduced to a small, scarcely visible denticle, which can only be seen 
from an internal view. The posterior denticulate or serrate ridge of 
some species is also frequently broken up into one or more denticles or 
may be entirely obliterated. This ridge also is more plainly seen from 
an internal view. 
