190 PROCEEDINGS OF THE NATIONAL MUSEUM Vou. 113 
ly colored specimens. Teneral specimens, which are usually much 
lighter in color than the normal, are usually impossible to identify 
on the basis of body color. 
ScaLes: The color pattern of scales, particularly on the prothorax 
and elytra, is often of value as a specific character (as is shown in 
the descriptions and discussions of S. quadrifer, S. albonotatus, and 
S. pusio). Some groups of species, such as those of the S. discoideus 
group, with dark maculae on their prothoraces and elytra, or the 
species of the S. lineolatus group, with elytral vittae, may be distin- 
guished by scale patterns. Unfortunately, the scales are easily rubbed 
off the specimens, and such specimens are difficult to identify if 
critical characters involve the scales. In addition, the scales may 
become saturated with the body oils of the specimens, and this may 
cause the scales to appear different in color than they were originally. 
Rostrum: The general shape, length, and pitting or sculpturing of 
the rostrum are usually fairly consistent in a given species, and often 
are important as distinguishing features of a species, groups of species, 
and subgenera. For example, the subgenus Desmoris may be distin- 
guished from the other subgenera by the long polished rostra of the 
females in that subgenus. Smicronyx lepidus Dietz has a very stout 
gibbous rostrum, which is important in diagnosing that species from 
the rest of the species in the S. qguadrifer group. The rostrum of S. 
cinereus Motschulsky has been shown to be significantly shorter before 
the antennal insertions than that of a similar species, S. obscurus new 
species (see the discussion of S. obscurus). 
Heap: No really significant characters have been found on the 
head, but as can be seen in the descriptions, there is some variation 
between species in color, surface texture, and scales of the head. 
ANTENNAE: As is mentioned in the description of the subgenera 
and as can be seen in the measurements of the species, the relative 
length of the second and third funicular segments varies from one 
species to another, but is usually similar among the species of a given 
subgenus. In a few species, such as S. sparus Casey, the antennal 
club is glabrous at the base. No differences other than those men- 
tioned have been found useful as taxonomic characters. 
ProtrHorax: The shape of the prothorax is often similar between 
species of a given group, as in the species of the S. corniculatus group, 
or the S. obtectus group, or the S. ovipennis group. In such instances, 
the shape of the prothorax may be useful in distinguishing one group 
of species from an otherwise similar group. For example, the species 
of the S. ovipennis group have a strongly rounded prothorax, but the 
prothorax of the species of the S. abnormis group is only slightly 
rounded at the sides. 
