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. Jeffreysii. 
XXXVIII.—On the Systematic Value of Rhynchophorous Coleo- 
ptera. By Joun L. Leconts, M.D.* 
In the empirical arrangement of the families of Coleoptera, 
which has resulted from the adoption of the tarsal system of 
division, the families contained in the great natural group of 
Heteromera are followed by the Curculionide and Scolytide, 
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 Cerambycide 
and Chrysomelide, 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 antenne, 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 cox, 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 antennz, or excessive length of palpi. 
On the contrary, we find in the Rhynchophora that the in- 
* From ‘Silliman’s Journal’ for July 1867, being an abstract of a 
memoir read before the National Academy of Sciences at Washington, 
Jan. 24, 1867. 
