PROCEEDINGS 



america:n^ philosophical society. 



YoL. XY. DECEMBER, 18t6. No. 96. 



THE RHYNCHOPHOEA OF AMERICA, NORTH OF MEXICO. 

 By John L. LeConte, assisted by George H. Horn.* 



PREFACE. 



The task that I have attempted to perform in the present memoir, is a 

 very difficult one, and I feel that it has been accomplished very imperfectly. 



It is, namely, from the study of the very small material represented in 

 the fauna of temperate North America, to induce entomologists to investi- 

 gate those Coleoptera, which have been heretofore classed as Curculionidce 

 and some allied, but ill-defined families, from a completely new standpoint; 

 whei'eby they become isolated from all other Coleoptera. 



The characters which render necessary this isolation of the Rhyncho- 

 phora have been already exposed by me in some short memoirs, f and 

 their value has been recognized by several systematists of excellent ability, 

 although not to the extent to which I hope the present effort will render 

 them acceptable. These characters are mainly to be found in the form of 

 the basi-lateral elements of the head and prothorax on the under surface of 

 the body, and will be detailed in the Introduction. 



By these peculiarities of structure, as well as by their food, the Rhyn- 

 chophora are restricted to a more uniform type of organization than is exhi- 

 bited in the normal Coleoptera; but at the same time being represented by 

 an immense number of species, the generic modifications are very varied. 

 The difliculty of tabulating these generic forms in a manner to exhibit their 

 relations to each other is therefore greatly increased. 



I have previously expressed my opinion that the Rhynchophora, being 

 the lowest type of Coleoptera, are therefore geologically the oldest. Re- 

 garding then the fixity of insect types, as shown by the resemblance of an- 

 cient forms to those of the present time, the uniformity in food and manner 



*See Proceedings, 1875, 649 (Nov. I9th) ; 662 (Dec. 17th). 



t Vide infra, Introduction, p. ix. 



