268 COLEOPTERA OF NORTH AMERICA. 



Elytra usually covering the abdomen, rarely short; epi- 

 pleune usually distinct, rarely (some Phytoeciini) indistinct. 



Abdomen with five free ventral segments, the sixth visi- 

 ble in many males, and occasionally in both sexes. 



Legs variable, usually slender, thighs frequently strongly 

 clubbed, hind coxee transverse, frequently inclosed exter- 

 nally by prolongation of epimera of metathorax. Tarsi 

 with joints 1-3 furnished beneath with brushes of hair, 

 sometimes wanting on the 1st and 2d joints of hind tarsi; 

 3d joint emarginated or bilobed, 4:th joint nodiform, small, 

 connate with 5th joint ; claws simple, rarely (Phytoeciini) 

 appendiculate or cleft, paronychiuni slender and distinct in 

 Prioninns, wanting in the others. 



A great family, containing an immense number of species, 

 which live in the larval state exclusively on the woody parts of 

 plants. The species are remarkable for large size, beauty of 

 color, or elegance of form, and have been, on these accounts, 

 great favorites with collectors. Nevertheless their classification, 

 and even, the definition of the family, present difficulties which 

 have been called insuperable by every systematist who has yet 

 attempted the task. 



The species are easily recognized, the chief variations being 

 only those of size, dependent probably on the quantity of food 

 obtained by the larva, or the excellence of its digestive power. 

 At any rate, the differences appear to be individual and not in- 

 dicative of races. The genera are, on the other hand, extremely 

 indistinct, as at present defined, for the reason that the species 

 frequently differ not only by the usual specific characters of form, 

 color, sculpture, etc., but by structural peculiarities of consider- 

 able moment, sometimes sexual, sometimes asexual. By regard- 

 ing these peculiarities as of generic value, the number of genera 

 (as in birds) has been vastly and unnecessarily increased, and 

 the system of classification correspondingly diluted, so that the 

 more essential points of resemblance between allied forms are 

 lost sight of, and the arrangement becomes quite artificial. 

 Frequent reference will be made in the following pages to the 

 misplacement of genera by the best authorities ; and, also, what 

 tends to greater confusion, to errors of description in several 

 of our genera, which lead tO an incorrect appreciation of their 

 relations. 



