Dr. J. L. Leconte on the Rhynchophorous Coleoptera. 291 



The only British species with which this Goby might be con- 

 founded, and to which it is evidently allied, is Gobius rhodo- 

 pterus (Gthr.) ; however, this latter species is said to have the 

 interorbital space broader, its width being equal to one-half of 

 the diameter of the eye (Cuv. & Val. xii. p. 50) ; and M'Coy, 

 who examined two Irish examples, describes the snout as " very 

 short, tumid, and convex," which character cannot be applied 

 to G. Jeffrey sii. 



XXXVIII. — On the Systematic Value of Rhynchophorous Coleo- 

 ptera. By John L. Leconte, M,D.* 



In the empirical arrangement of the families of Coleoptera, 

 which has I'esulted from the adoption of the tarsal system of 

 division, the families contained in the great natural group of 

 Heteromera are followed by the Curculionidse and Scolytidse, 

 which, more or less subdivided into smaller families, have been 

 supposed to establish a linear relation between the rostrated 

 Heteromera [Salpingus, Rhinosimus, &c.) and the Cerambycidse 

 and Chrysomelidse, the great types of the Pseudotetramera or 

 Subpentamera of various authors. 



It is the object of the present investigation to determine the 

 limits and the relations of the first-mentioned of these types, 

 the Rhynchophora. 



The inferiority of this type is manifested not only in the 

 larval condition by the limited number or absence of visual 

 lenses, the want of locomotive appendages, the feeble develop- 

 ment or entire want of antennae, and the unchitinized epidermis, 

 but also by the combination in the imago of characters belong- 

 ing to a perfectly developed organism with others pertaining to 

 an inferior grade in the scale of Coleoptera. 



Thus, for instance, while we perceive, in the other series of 

 beetles, that the lower forms retain certain larval characters (as 

 evidenced by the extension of the coxae, the imperfection of the 

 anterior coxal cavities, the softness of the integuments, and the 

 want of centralization in the abdomen), all such degradational 

 characters are absent in the Rhynchophora. 



Other characters representing low grades in their respective 

 series do not appear in the Rhynchophora — such as vegetative 

 growth of the organs of sense, indicated by pectinate or flabel- 

 late antennse, or excessive length of palpi. 



On the contrary, we find in the Rhynchophora that the in- 



* Fi'ora ' Silliman's Journal' for July 1867, being an abstract of a 

 memoir read before the National Academy of Sciences at Washington, 

 Jan. 24, 1867. 



