



INTRODUCTION. 



The present volume of the Coleoptera section of the Central-American fauna deals 

 with the two allied Tribes Pectinicornia and Lamellicornia, well-defined groups which 

 include many of the largest and most striking forms of the order. The genera repre- 

 senting the two tribes were placed by Linnseus and other early systematists, apparently 

 under a vague, but not less true, sense of their superior organization, at the head of 

 the whole Coleopterous series, a position from which they have since been deposed in 

 favour of the less specialized Cicindelidse and allied groups of the Adephaga. The 

 higher specialization of the Lamellicornia is clearly shown in the tendency they display 

 to consolidation of parts of their external structure, especially the mouth-organs, the 

 ligula with the mentum, and the labrum with the clypeus or epistome, and still 

 more clearly in the concentration and reduction in number of the ganglia of the 

 nervous system. 



The two tribes were considered as forming one only by the eminent specialists 

 Erichson and Burmeister, and were separated by Lacordaire in hi& classical ' Genera 

 des Coleopteres,' in 1856, chiefly on the ground of the immobility of the antennal 

 lamellae, the same being movable like the leaves of a book in the more highly 

 organized Lamellicornia. This constant difference is, however, supplemented by many 

 other important and significant characters, which, though constant within subordinate 

 groups of each respectively, do not apply to the whole tribe and are therefore of minor 

 systematic value, though indicating sufficiently distinct tribal types of form and lines 

 of development. 



With regard to the contents and relations of the Central-American fauna of Pecti- 

 nicornia and Lamellicornia, the two tribes present such different aspects that they 

 must be considered separately. 



In Pectinicornia our fauna is exceedingly poor in the chief family of the tribe, viz. 

 the Lucanidas, but, on the other hand, exceedingly rich in the other and more aberrant 



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