[ 498 J 76 



• 



1. If the tarsi are simple and the antennae filiform, the species may 



belong to some one of a number of diverse families (Carabidae, ElateridaB, 

 Mordellidae, Melandryidse, Cistelidae, and a few smaller fam'lies) ; biu 

 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 the antennce clavate or capitat-e, the in- 

 sect may 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 in- 

 quiry. A few apparent exceptions exist in the heteromerous families 

 of DiaperidsB and Tenebrionidse, but the former can be usually distin- 

 guished by their perfoliate antennae, and the antennae of the Tenebrio- 

 nidae are usually so slightly enlarged towards the tip as scarcely to be 

 entitled to the name of clavate. Other partial exceptions are found in 

 the family of Scolytidae, or short horned wood-borers, all of which have 

 strongly clavate antennae, and some of which have simple tarsi j but 

 many of them have the last joint but one slightly bilobed. 



3. If the last joint but one of the tarsi is bilobed and the antennw fili- 

 form, the insect belongs to the family of long-horned borers {Ceramby- 

 cidce), or to tbat of the plant-beetles proper {Chrysomelidce, etc.) The 

 tarsi thus formed anj almost always spongy on the under side. Only a 

 few partial exceptions to this rule are found, and these are in the he- 

 teromerous families of CEdemeridae, Anthicidae, and a few others ; but 

 in these the tarsi are usually but slightly dilated, and but little, or not 

 at all, spongy beneath. 



4. If the tarsi are bilobed and the antennce clavate, the species belongs 

 to the tribe of snout-beetles {Curculionidce), in the terramerous section, 

 or to the family of Erotylidse, or that of Coccinellidae, in the trimerous 

 section. 



5. Beetles with distinctly serrate antennce belong almost exclusively 

 to the families of Serricornes proper, in the pentamerous section ; but 

 this rule also has a few exceptions. The pea and bean weevils {Bru- 

 chidce), in the tetramerous section, usually have the antennae decidedly 

 serrate ; and a few small families of the division of Trachelides, in the 

 heteromerous section, {Rhipiphoridce and Pyrochroidce,) usually have 

 the antennae serrate in the females, and flabellate or branched in the 



males. 



6. All beetles with lamellate antennce belong to the division of Lamel- 



licornes proper, in the pentamerous section. Only in very rare instances 

 the branches of a pectinate or flabellate antenna are somewhat flattened 

 so as to resemble the true lamellate. An example of this is found in 

 the little beetles of the genus Phloeotribus in the family of Scolytidae. 



