18 Introduction 



that have the lamellate antennae or anything approaching them, except 

 perhaps a few Scolytids. Dr. Sharp's course in treating them first, 

 before even the Adephaga, is perhaps a consequence of their isolation 

 being prominent in his thoughts. Dr. Leconte also considered but 

 rejected the same course. The final disposition of this question must 

 be left for the future; I am unwilling to add another sub-order, though 

 I can see many reasons in favor of doing so; such reasons, however, are 

 part of those that prevent me treating Rhynehophora as a sub-order. 



The isolation of the Staphyliniformia by recent authors seems to be 

 based on very strong grounds. In degree it may be less complete than 

 that of Rhynehophora and Lamellicornia, for there are forms like 

 Sphaerites that have been placed in Polyformia. But there must be 

 such differences in degree of isolation of series, families, tribes, genera 

 and species, for we can never expect an absolute equality in that respect. 



The isolation of Phytophaga is even less complete ; many authors 

 unite them with Rhynehophora, others see a remote connection with 

 some families of Polyformia. It is difficult indeed to frame a definition 

 for them based on adult characters alone. Still the term has long been 

 used and is perfectly understood as one admirably covering Ceramby- 

 cidse, Chrysomelidse and Bruchidse as a series of plant-eating families. 



Still more difficult to define as a whole are the numerous smaller 

 series here grouped under the names Polyformia, Palpicornia and Clavi- 

 cornia. They are in fact what remains after separating the larger 

 and more strongly characterized series. They include some series like 

 Malacodermata and Sternoxia that though smaller in number of species 

 involved are very distinct; the distinctions, however, occur in structures 

 that have not been used in making primary divisions, and are perhaps 

 in that sense of less importance. The Rhynehophora seem to me very 

 nearly of the subordinal importance that Leconte gave them; those 

 included above seem nearest to them in degree of important difference. 

 I have reduced the Rhynehophora somewhat unwillingly because I 

 feel that their isolation is less than that of Adephaga, but I cannot 

 still further reduce them by elevating more, even of the best defined 

 series in Polyformia, to equivalent rank. 



Progressive Modification of Various Structures 



Before discussing the sequence in which the series as defined above 

 should be arranged, I would like to state the general conditions under 

 which the order has become specialized in different directions and the 



