of the Amazon Valley. 45 



throughout long geological epochs. The diversity of specific 

 forms seems endless, running into infinite varieties of grotesque, 

 ornamented, and extraordinary shapes ; and nearly every species 

 has structural peculiarities for its specific characters ; so that in 

 no family can genera be made so easily and so numerously as here. 

 Analysis is too easy, and has already been pushed, perhaps, to 

 too great an extent. 



The Lamiaires, as far as they are represented in the Amazo- 

 nian fauna, seem to present six different types of form : but in 

 none are the characters quite constant ; they can only be con- 

 sidered as very general, but seldom apply to the whole of the 

 species or genera. I have taken into consideration most of the 

 parts of structure employed by Messrs. Leconte and Thomson, 

 and have brought into prominence others which were neglected 

 or only considered subordinate by them, viz. the shape and re- 

 lative length of the basal joint of the antenna?, the tubercle and 

 groove of the middle tibia?, and the claw-joint and claws of the 

 tarsi. The parts of the mouth, which offer sure characters in 

 most other families of Coleoptera, are here of scarcely any 

 systematic value. The palpi only occasionally furnish generic 

 characters. The ligula, otherwise a very important organ, varies 

 greatly in species very closely allied in all other characters. 

 Under each subtribe I have quoted such of M. Thomson's groups 

 and divisions subordinate to it as are represented in the Amazon 

 region. 



Subtribe 1. AcANTHODERiTiE. Basal joint of the antennae 

 shorter than the third, forming an elongate-pyriform club, 

 very slender at the base. Middle tibia with the tubercle 

 and groove on its outer edge conspicuous. Anterior aceta- 

 bula generally angulated externally, the suture more or less 

 gaping, but sometimes (Steirastoma) entirely closed. Tarsi 

 simple. 



Acanthoderita?, Acrocinita?, Oreoderita?, Dryoctenitse, Poly- 

 rhaphita?, and Anisocerita?, Thorns. 



Subtribe 2. Acanthocinit^:. Basal joint of the antenna? much 

 elongated, as long as or longer than the third. Middle tibia 

 almost always with the tubercle and groove conspicuous. An- 

 terior acetabula ch-cular, the suture being closed or nearly so. 

 Head narrow. Tarsi simple. 



Acanthocinita?, Trypanidiita?, Colobotheita?, Thorns. 



Subtribe 3. Lamiit^:. Basal joint of the antenna? moderate 

 in size, forming an oblong club thickened from base to tip. 



