Preface. vii 



The families of the Coleoptera are mainly those recognized by 

 Sharp and Ganglbaur, and largely reverse the familiar sequence 

 given by Le Conte and Horn. Two or three orders do not occur 

 in North America, but have been added to the key for the sake of 

 completeness. A few families absent in North America have 

 representatives in Central America or the West Indies, and these 

 also have been included. 



The present system of insect classification has gradually been 

 evolved by many workers in almost innumerable contributions 

 published during the course of more than a century. During this 

 time systems have been proposed, wholly or partially discarded, 

 or incorporated into new ones. The task of the writers has been 

 little more than to compile from this existing literature the most 

 recent ideas, and they have gleaned from so many sources in various 

 languages that it is impossible to refer to all in detail. To some 

 extent this is also true of the illustrations which have been verv 

 largely redrawn from published figures, by Beirne Barrett Brues, 

 the wife of one of the authors. The original source of the drawings 

 is indicated on the explanations to the plates by the name of the 

 author in parentheses, although it must be stated that many have 

 been simplified, differently lettered, or otherwise modified to adapt 

 them to the purpose of the present manual. 



While family groupings should be of equal rank throughout the 

 animal kingdom, they are not always coordinate, since they are 

 concepts rather than concrete divisions and hence are subject to 

 the variability of ideas. That the specialist is apt to narrow his limi- 

 tations can be seen by the constantly increasing number of families 

 proposed. For example, the old group Tachinidae, geologically 

 one of the most recent of insects, has been segregated into scores 

 of so-called families. If this course is accepted in one group it 

 carries with it a tacit elevation of all other ranking minor groupings 

 and thus the family concept becomes altered. Since views on 

 classification irresistibly shift through such changes and are con- 

 stantly diverted by the discovery of annectant forms, no taxo- 

 nomic scheme can be considered complete or final. While the 

 writers have to some extent attempted to keep the family groupings 

 balanced, yet they fully appreciate the futility of such an endeavor 

 and present the following outline as seemingly that most widely 

 accepted by present-day entomologists. 



