19 LeConte on the Pselaphide of the United States. 
men. The first effort to decompose this tribe has herein been 
made by joining the Oxytelint and Omalini with the Pselaphi ; 
and in future memoirs, I hope to point out how some other 
portions of the Brachelytra may be disposed of. 
The results already obtained by systematists in the forma- 
tion of these two heterogeneous groups, with such opposite 
characters, and some considerations derived from the larve, 
will point out the proper course to be taken in these invest- 
igations. 
On looking at a number of larve of Coleoptera, we at 
once perceive great differences in their tegumentary system. 
Some are cylindrical and soft, while others are more or less 
flattened, and protected by corneous scuta. Accordingly, 
there will be some embryonic groups having a soft consist- 
ence, and these will belong to the series with soft Jarve ; other 
embryonic forms, derived from corneous larvee, must have 
likewise a hard covering, and these will retain the free multi- 
articulate abdomen, and will in fact be Brachelytra. 
As the corneous tegument of some larve of Elateride and 
Tenebrionide is of a different structure, since it is not 
arranged in a scutate manner, but is a hardening merely of 
the membranous skin seen in other larvæ of the same tribes, 
we must by no means infer, that the lower members of these 
groups are Brachelytrous. In such cases, the hardening being 
merely a further development of the usual structure, will 
merely serve to point out the higher members of the groups 
in which it occurs. 
AUTHORS CITED BELOW. 
Say, in Journ. Academy of Natural Sciences of Philadel- 
phia, Vol. IV. 1 
Errcuson, Die Kafer der Mark-Brandenburg. Berlin, 
1837. 
Avsé, in Guerin’s Magazin de Zoölogie. 1 
Avsé, in Annales de la Société a a de France, 
9d séries, tom. II. 1844. 
