viii PREFACE. 



of life, and the immense nimiber of genera in this complex, with -which we 

 are dealing, we have a right to expect that there will be a proportionally 

 larger survival of unchanged descendants of those species or genera which 

 were tirst introduced. We will, therefore, have a more perfect series of 

 connecting forms than can be found in other orders of insects, whose 

 methods of life expose them to the influences of destruction or modification 

 by external circumstances. 



Nevertheless, the arrangement which I have adopted, will show in the 

 larger groups or tribes, a dominance within the limits of each tribe of one 

 tjqjical modification of structure, with variations in the direction of modi- 

 fications which become dominant, and definitive in other tribes. 



It thus comes to pass that, neglecting the essential characters of the tribe, 

 to which the species may properly belong, the definition of the genus will 

 approximate in language very closely to that of some other genus, belong- 

 ing to a very distinct part of the series. 



in other words, the genera belonging to several tribes will agree with 

 each otherin similar characters of less value than the tribal characters. 



What I have just said regarding genera is equally true in respect to 

 species. The form, color and sculpture in many instances are repeated in 

 tribes which from their geographical distribution and method of life can- 

 not be supposed to have any immediate genetic derivation. Instances of 

 this kind of resemblance will be mentioned both in the Introduction, and 

 in the body of the memoir. 



I have no theory to propound regarding this very complex system of 

 cross resemblances. They are certainly not the result of mimicry, and pro- 

 bably not of natural selection, or any other name of an idea which has yet 

 been suggested. A deeper insight into the phenomena of organic nature, 

 which may, perhaps, be acquired by our successors would give us a more 

 reasonable explanation of these resemblances.* 



My best thanks are due to my excellent collaborator. Dr. G. H. Horn, 

 for his careful study and classification of the family OtioThyncMdce, cer- 

 tainly one of the most difficult among the Rhynchophora, and next to the 

 genuine Curculionidm, the largest. I also owe my kindest acknowledg- 

 ment to Mr. G. W. Belfrage, for a large series of specimens from Texas; to 

 Messrs. H. G. Hubbard and E. A. Schwarz, for very full series from Michi- 

 gan and Florida; to the Museum of Comparative Zoology of Cambridge for 

 the loan of the Zimmermann collection, mostly from the Southern States; 

 and to Messrs. E. P. Austin, W. Jiilich, and Prof C. V. Riley for large 

 sets of specimens from various parts of the country. Other friends have 



* Mr. A. R. Wallaco in his suggestive address to the Biological Section of the 

 British Association for the Advancement of Science, held at Glasgow, 1876, has 

 expressed himself quite clearly concerning the inadequate explanation of the 

 resembU\nces between objects of diverse genera, tribes and families, which has 

 thus far been offered. lie comments at length on a certain relation between 

 color and locality, not dependent on protective tendencies. This, however, is 

 only one of several groups of curious facts which will be developed by more pro- 

 longed and minute observation. Vide Nature, Sept. 7th, 1876, p. 404, 



