H. C. FALL 291 



A REVISION OF THE NORTH AMERICAN SPECIES OF 

 PACHYBRACHYS 



BY H. C. FALL 



For reasons, which to the initiated are obvious and sufficient, 

 no realh^ serious attempt at a comprehensive treatment of our 

 species of Pachyhrachys has been made since the appearance of 

 Suffrian's paper on the North American CryptocephaUni. In 

 1880, Dr. LeConte essayed to give a table for the separation of 

 the more easily defined species, but in addition to the twenty- 

 nine thus treated, he was compelled to append a list of at least 

 twenty forms which were too indefinite or too little known to 

 permit of tabulation. 



Briefly stated, the natural conditions which have discouraged 

 any attempt at a systematic treatment of our species of this 

 genus are, — the great number of species involved; their indefinite- 

 ness, due to the lack of salient diagnostic characters, and the 

 great individual variability, more especially in the superficial 

 characters of sculpture and markings, upon which specific dis- 

 tinctions have been largely based. In addition to these inherent 

 difficulties, a further serious obstacle to progress has been the 

 impossibility of recognizing — in the absence of types — a consider- 

 able number of the Suffrian species, the descriptions of which, 

 though lengthy, are of little use for purposes of identification. 

 This last obstacle has been in part overcome by the opportunity 

 of examining a number of the Suffrian types kindly sent to Mr. 

 Bowditch and to the writer by Dr. Taschenberg of Halle, through 

 the intercession of Dr. Walt her Horn of Berlin. The natural 

 difficulties are of course still with us, and their complete solution 

 is purely a question of time and experience — and will certainly 

 require a large measure of both. The writer realizes — probaljly 

 more fully than any one else — the shortcomings and incomplete- 

 ness of the present revision, but to wait the solution of all ques- 

 tions of relationship and synonymy would simply mean that the 

 results of an already protracted study wouM never be published. 

 It is, moreover, undoubtedly true that the interest of students and 



TRANS. AM. ENT. SOC, Xl.I. 



