AMERICAN COLEOl'TEKA. 387 



REVISION OF THE €iENEKA AMD SPECIES OF 



CEUTOKIIYNCHIMI I.MIABITIMG 



NORTH AMERICA. 



I5Y WILLIAM (i. BIETZ, M.I). 



Since the publication of my paper on the Desinori of North 

 America, the greater part of my spare time lias been devoted to a 

 study of our North American Ceutorhynchini. To make these 

 .studies as complete as possible I have also examined a large number 

 of foreign," especially European species, representing, with one ex- 

 ception (Mecysmoderes), all the genera of this tribe described by 

 Lacordaire. 



Before proceeding to the elucidation of the subject proper, I desire 

 to call attention to a few characters which, to the best of my knowl- 

 edge, have escaped observation heretofore. The formation of the 

 ventral segments presents certain modifications, of which I have made 

 use in the classification of the genera. 



1. The second ventral segment fully as long or longer than the 

 two following segments together, the latter always short, the third 

 segment not narrowed on the sides by a prolongation of the hind 

 angles of the preceding segment. PI, xiii, fig. 19«. 



2. The second ventral segment scarcely as long or shorter than the 

 two following segments, hind angles prolonged, the prolongation in- 

 tervening to a greater or less extent between the third segment and 

 the lateral margin of the abdomen and showing thus a tendency to 

 the Tychini. PI. xii, fig. 1. 



Another character, though of a sexual nature only, is this, that in 

 the majority of the species the middle and posterior tibise (generally) 

 of the males are unguiculate at the apex, while unarmed in the 

 females, and occurs especially in the fir.st three subtribes. 



Aside from this last-mentioned character the sexes can, as a rule, 

 be readily distinguished. The males have the beak stouter and less 

 elongate, the antennae less slender and inserted nearer the apex 

 (rarely the same in both sexes), and by the fifth ventral segment 

 being subtruncate and frequently foveate. 



TRANS. AM. K.VT. SOC. XXIII. SEPTEMBER. 1896 



