l'2G 
ARCANA NATURÆ. 
opaca, Say (considered by Lacordaire as a genuine Asida) from the other species, placed by me in 
Pelecyphorus, is the distinct fissure each side of the gula, permitting the base of the maxillæ to be seen ; 
and it was for this reason that I placed A. opaca in Euschidcs, which differs only by the posterior 
angles of the thorax not being distinct; a character certainly not of generic value; and a slight dif- 
férence in the form of the mentum. 
AMPHIDORA, Esch. 
14. A. osculans, oblonga, atra nitida, pilis longis fulvis dense vestita, thorace subtransverso, late- 
ribus valderotundatis, confertim punctato , postice angustato, angulis posticis minutis redis; elytris sma- 
tim punctatis, interstitiis sat dense rugosis et punctatis. — Long. 15 mill. — Tab. XII, fig. 4. 
Leconte, Annals of the Lyceum of Natural Jlistory of New York, V, 136. San Diego and Santa Isa- 
bel, California. Resembles in form A. iittoralis, Esch., but is much larger. The anterior tarsi of the 
male are not dilated as in that species (as tliey also are, but more feebly in A. mgro-pilosa, Lee.), but 
the posterior tibiæ, about one-fourth of their length from the apex, on the inner margin, are armed 
xvith a small acute tooth. 
TANARTHRUS, Lee. 
15. T. salinus, depressus, rufo-testaceus, tenuiter cinereo-pubescens, subtiliter punctulatus, capite 
thoraeeque nitidis, illo magno basi emarginato, antennarum articulo ultimo præcedentes 4 æquante. — 
Long. 6 1/2 mill. — Tab. XIII, fig. 8. 
Leconte, Armais of the Lyceum of Natural Jlistory of New York, V, 156 ; Proceedings of the Academy 
of Natural Sciences of Philadelphia, VI, 104. Colorado Desert, on the margin of a saltlake, flying over 
the half-dried mud like a Bembidium. 
This genus belongs properly to the family Anthicidœ, the eyes being entire. I regret that, by a mis- 
conception of my observation [Proc. Acad., VII, 277) regarding a supposed species of Xylophilus, 
X. (?) basalis, Lee., which lias the eleventh joint of the antennæ elongated as in Tanarthrus, Lacor- 
daire should hâve considered that I meant to apply the expression « but the eyes are deeply emargi- 
nate, as in the other species of Xylophilus » to Tanarthrus. It was intended to show that the species 
under considération X. (?) basalis, although possessing the antennæ of Tanarthrus did not belong to 
that genus, nor even to the same family, but was, in essential characters, a Xylophilus. The genus 
Tanarthrus, in fact, finds its place in the family Anthicidœ, and in Lacordaire’s synoptic table ( Gen . 
Col., Y, 591), would enter immediately after Anthicus, from which it differs by the last joint of the an- 
tennæ being elongated and almost divided into two, and by the penultimate joint of the tarsi not 
being bilobed. 
CYSTEODEMUS, Lee. 
16. C. abmatiis, obscure œneo-olivaceus, opacus, capite punctato, postice canaliculato, occipite conico ; 
thorace punctato , utrinque spina acuta armato; elytris antrorsum angustatis, dorso antice late depressis, 
spatiis impressis, irregularibus, reticulatis. — Long. 11-18 mill. — Tab. XIII, fig. 3. 
Leconte, Annals of the Lyceum of Natural History ofNew York, Y, 158; Proceedings of the Academy 
of Natural Sciences of Philadelphia. VI, 330. Colorado Desert, California, on Larrea mexicana, or 
creeping on the sand. The other species of this genus, C. Wislizeni, Lee., has the elytra globose, of a 
beautiful blue color, cancellate with large punctures and the thorax pentagonal ; it is found in Ari- 
