312 
LE CONTE.—LONGICORN COLEOPTERA 
the following pages have been made to contribute greatly to this very desirable object. 
Indeed, the genera Leptiira and Strangalia might perhaps have been merged together, 
since they only differ in the degree of prominence of the posterior thoracic angles; 
this character is found to be variable, so that I have great doubt of its generic value. 
Whilst thus exposing the faults of the heretofore arrangements of this group, it is 
by no means presumed that the present scheme is unobjectionable. All that is 
claimed for it is, that it is more applicable to American species, as well as those 
European species which commonly occur in collections. 
The large increase of genera may be objected to, no less than eight new ones 
having been added to the Leptura alone, but these are recognized at once by certain 
peculiarities of habitus, and the characters on which they are founded are, so far as I 
know, invariable. The generic table appended to these remarks will render this 
sufficiently obvious. 
There does not appear to be much accurate parallelism between the European and 
American species of this family ; and most of the genera found in Europe are equally 
developed on this continent. An exception to this principle is found in Rhagium, of 
of which we have but a single species. Vesperus and Rhamnusium are peculiar to 
the old continent, but here Desmocerus represents the former and Ceniroderus the 
latter. Peculiar to America are Piodes, Gaurotes, and Typocerus, the five other new 
genera are distributed over both continents. There are two species of this group 
which are indigenous to Europe and America, viz ; Acmceops strigilata and Strangalia 
sexmaculata: they are confined to the Northern regions neither of them occurring 
south of Lake Superior. 
The genus Distenia will be found among the Cerambycida. I know not why it 
has been associated with the Lepturce, viilh. which its affinity is very slight: it is 
much more closely allied to Eburia and Cerasphorus. 
Before passing to the specific details of this tribe, it may be proper to say a few 
words on the characters which distinguish the LepturcB from other sections of the 
Longicornia, and to ascertain the true value of the division which they form. 
Longicornia have been divided by Latreille, Serville, and other authors, into three 
groups, Prionidce, Cerambycidce, and Lepturidce. The first group distinguished by 
the deflexed labrum, rudimentary inner-maxillary lobe, and the antennie inserted in 
front of the eyes. The second group has the head not narrowed into a neck and the 
antennae are placed between the eyes. The third is separated on the single character 
of the head being narrowed posteriorly into a kind of neck. The second group is 
again divided into two: Cerambycini, with porrected head and dilated palpi, and 
and Lamiarii, with deflected head and piliform palpi. 
This arrangement is very unsatisfactory, since by following it, we associate with 
Priorii, Asemum, Criocephalus, and other genera, which in form are true Callidia ; 
