ARCANA NATURÆ. 
121 
DESCRIPTIONS 
OF 
SOME GENERA AND SPECIES OF COLEOPTERA 
FROM THE VICINITY OF THE SOUTHERN BOUNDARY 
OF THE UNITED STATES OF AMERICA; 
BY JOHN L. LECONTE, IYI, D. 
The species described in the présent memoir hâve ail been previously made known 
by me in American publications cited below ; nevertheless, being mostly remarkable for 
their strange forms or singular affmities, I hâve thought that a more close knowledge of 
lhem would be of interest to the entomologists of Europe. 
I hâve therefore, with great pleasure, availed myself of the liberal offer of my friend, 
Mr. J. Thomson, to publish them by means of the very favonrable opportunity afïorded 
in the présent splendid work. The plates being published at intervals, and the text pre- 
pared at a great distance from the place of publication, it will be impossible for me to 
place the groups of insects represented in a natural order ; but in each part of the me- 
moir, the species contained in it will be arranged in accordance with the System usually 
adopted by entomologists. For this reason, I will place first : 
PLASTOCERUS, Lee. 
1. P. Schaumii, piceo-castaneus, helvo-pubescens, capite thoraeeque pilis longioribus erectis densius 
vestitis, Mo scabro, hoc antrorsum angustato, lateribus sinuatis, angulis posticis elongatis divergentibus, 
dense punctalo ; elytris striis nage impressis, interstitiis subrugosis ; pectore longius cinereo-pubescente. 
Long. 14 mill. — Tab. XIII, fig. 1. 
Leconte, Trans. Am. Phil. Soc., X, 502. San Diego, California; flying just before sunset, near the 
shore of the bay, in May and June. The female differs from the male by the pectination of the an- 
tennæ being very short, so that those organs become scarcely more than serrate ; the elytra also are 
more flattened and slightly déhiscent. 
The genus Plastocerus belongs to the tribe Campylini of Elateridœ, and forms with Aphricus, Aplas- 
tus and Euthgsanius, Lee., a small group distinguished by the labrum being indistinct. These four 
généra are ail found in California, and thus far Plastocerus alone is represented in any other part of 
the world. The general appearance of these four généra is very different ; Aphricus, with the front 
margined and the mandibles slender and prominent, the antennæ moderately serrate, has the form of 
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