INTEODUCTIOlsr. 



Rhyncliopliorous Colcoptera are those in which the posterior lateral 

 elements of the head* and prothoraxf coalesce on the median line of the 

 under surface of the body, so as to unite by a single suture. 



To the first of these characters there is no exception in the wide range 

 of the existing Coleopterous insects ; to the second there are two notable 

 discrepancies. The first is Nematidium,\ commonly classed with the 

 ColydiidcB, the other is the genus Cossyphus,$ which has been considered 

 as belonging to the Tenebrionidw, from the other members of which it 

 differs, not only by the structure of the under surface of the prosternum, 

 but by other characters, which require future study for a proper apprecia- 

 tion, of their importance. 



I might rest the definition of the Rhynchophora at this point, and pro- 

 ceed to indicate the different series and families into which, according to the 

 system I have developed, these insects should be divided, but before doing 

 so, there appear to me certain relations between the members of this sub- 

 order, which are well worthy of attention; and certain characters which I 

 have not had time to investigate fully, but which are indicated for the 

 guidance of those, who will in future adopt the views herein set forth. 



There are also certain characters common to all, or nearly all Rhynchoph- 

 ora, most of which I have mentioned in the two essays cited below. || 

 but which for convenience may be here briefly recapitulated : 



Isrt. There are no soft, larval, or imperfectly chitinized forms, or forms 

 with short elytra, exposed wings, or greatly multiplied antennal joints, 

 such as are of frequent occurrence among the normal Coleoptera, 



2d. There are none in which the side pieces of the prothorax arc separated 

 by suture from the pronotum, and very few in which even the lateral 

 margin is indicated; in many the prosternal sutures are distinct, but in 

 some even these are obliterated. 



3d. In none are the front coxal cavities open posteriorly, though in some 



* Le route, American Naturalist, Feb., 1875, ix, 112. 



t TJC Cuntr, American Journal of Science and Arts, July, !Sf57. 



This Delias has been recently described by Reitter, Verhandl. naturforsch. 

 Yereines in Brunn, 1870, as belonging to the Trogositidu>, under the name 

 Filumin. 



I Horn, Tr. Am. Knt. Sue. isiiS, p. x. 

 Am. .lourn. Sc. and Arts, July, 1867; American Naturalist, July, 1S71. 



xi 



