AMERICAN COLEOPTERA. 223 



did not allow him to enter fully into the discussion of the subjeot. 

 As it is the isolated character of his material has led him to make 

 too many divisions and genera, a pardonable mistake for that reason. 

 I cannot allow the present occasion to pass without special mention of 

 C. Gr. Thomson's work. It is filled with important discoveries, new 

 ideas and useful hints applicable to larger fields of study, and I am 

 unable to understand why he appears to be so little appreciated by his 

 European coteniporaries. With us it is usual before undertaking any 

 work in which he has studied similar genera to refer to his book to 

 avoid unnecessary labor, as it has more than once occurred to me to 

 find characters already known to him which I had obtained after long 

 and patient search. 



The value of the coxal structure as a means of separating the 

 family into tribes has already been intimated, and the following table 

 is offered for the consideration of students. 



Posterior coxae simple. 



Anterior coxse more or less transverse at base and with trocbantin. 

 Anterior coxal cavities open behind. 



Posterior coxee contiguous Silphim. 



Posterior coxse separated. 



Anterior coxse prominent. Abdomen with five segments. ..Lyrosomini. 

 Anterior coxse not prominent. Abdomen with six segments. ..Pinodytini. 



Anterior coxal cavities closed behind Anisotomini. 



Anterior coxae cylindric-conic, without trochantin, the cavities closed behind 



often widely Cholevini. 



Posterior coxse laminate. 



Anterior coxse with trochantin, the cavities closed behind Clambi.vi. 



These characters are so easily expressed in words as to need no 

 further comment, and under the descriptive remarks will be found 

 comments on the various lines of affinity existing between the tribes. 



In the tables of the genera of the various tribes will be found not 

 . only our own genera but all those described up to the present time, 

 which are placed in position from an examination of the genera in 

 nature with few exceptions. 



For the types of many European genera I am indebted to M. Aug. 

 Salle of Paris, and Dr. Dohrn of Stettin. For the material for 

 the elucidation of our own fauna outside of my own cabinet. I 

 am indebted to Dr. Leconte, and Mr. Ulke of Washington, both 

 of whom have allowed unrestricted use of their material. Nearly 

 all the species described by Mannerhoim, from Alaska, have been 

 seen and described here from types sent by Maunerheim or Chaudoir 

 to Dr. Leconte. 



