t 
34: THE ORDER OP COLEOPTEKA. 
have a part of these joints widened but not bilobed in the males, but 
here it is a sexual distinction, and is confined to the anterior feet. 
These small Pentamera, with variable tarsi, almost always have 
strongly davate antennae, except the Staphylinidae, and these are dis- 
tinguished at once by their short wing-covers. The true Tetramera, on 
the contrary, have the antenna; filiform, or at most slightly and gradu- 
ally enlarged toward the tip, except the snout-beetles ( Curcutionidie ), 
and these are readily known by their elongated rostrum. 
If, then, the student have in hand a small beetle whose place in the 
system he cannot determine with certainty, from the number of tarsal 
joints, let him first observe whether these joints are slender and sim- 
ple or dilated and brush-like beneath, with the last joint but one deeply 
notched or bilobed ; and then let him examine the antenna;, and observe 
whether they are slender and filiform, or whether they are decidedly 
enlarged at the end, either gradually ( clavatc ), or abruptly {capitate). 
1. If the tarsi arc simple and the antenna} filiform , the species may 
belong to some one of a number of diverse families ( Carahidie , Elater - 
■idee, Mordellidce , Mclanilryida ', Cistclida >, and a few smaller families) ; 
but the beetles with this combination of characters are rarely of very 
small size, and they are, therefore, the more easily determined by their 
other characters. 
2. If the tarsi are simple and thf antenna: clavate or capitate , the in- 
sect rnafr be referred, with very few exceptions, to some one of the fami- 
lies of scavenger beetles in the pentamerous section. This rule embra- 
ces a large proportion of very small sized beetles, and will, therefore, 
be found of great use to the student in narrowing the field of his 
inquiry. A few apparent exceptions exist in the licteromerous families 
of Diaperidas and Tenebrionidse, but the former can be usually distin- 
guished by their perfoliate antenna;, and the an ten me of the Tenebrio- 
nida; are usually so slightly enlarged toward the tip as scarcely to bo 
entitled to the name of clavate. Other partial exceptions are found in 
the family of Scolytkhe, or short horned wood-borers, all of which have 
strongly clavate antenna;, and some of which have simple tarsi ; but 
many of them have the last joint but one slightly bilobed. 
3. If the tarsi are dilated and bilobed. and the antennae filiform, the in- 
sect belongs to the family of long-horned borers ( Cerambycidw ), or to 
that of the plant-beetles proper ( Ghrysomelidce , etc.) The tarsi thus 
formed are almost always spongy on the under side. Only a few par- 
tial exceptions to this rule are found, and these are in the heteromerous 
families of CEdemeridffi, Antliieidae, and a few others; but in these the 
tarsi are usually but slightly dilated, and but little, or not at all, spongy 
beneath. 
