142 
Psyche 
[June 
Mychocerus Erichson 
Mychocerus Erichson, 1845: 292. Type species, by monotypy, M. ferru- 
gineus Erichson. 
This New World genus contains five species, two of which occur 
in America north of Mexico. The described Seychelles species, M. 
alluaudi Grouvelle, was transferred to Lapethus by Hinton (1936). 
Grouvelle (1895) also included Philothermus gibbulus Reitter 
(1876), without giving his reasons; although Reitter’s type has 
not been seen, the description of gibbulus could hardly apply to a 
species of Mychocerus. The species of Mychocerus may be dis- 
tinguished by the small size and flattened form, 9-segmented antennae 
with a 1 -segmented club, anteroventral antennal cavities, and seriate 
elytral punctation. The literature is somewhat confused as to the 
type species for this genus. In the original description, Erichson 
mentioned that three species were included in his genus, but he 
named one from Cuba, (( M. ferrugineus Nob.” Since the genus was 
described in the same paragraph, this must constitute the species 
description as well, and thus M. ferrugineus is the only included 
species and the type. We have not seen the Cuban species, but we 
are assuming that it is congeneric with M. depresses, which LeConte 
(1869) placed in Mychocerus , and which is usually considered the 
type. 
Key to the North American Mychocerus 
1. Sides of pronotum gradually converging near apex, not angu- 
late; lateral lines of mesosternum subparallel for most of their 
lengths, abruptly converging anteriorly, each line posteriorly 
forming an abrupt angle (about 120°) with the metasternal line 
(fig. 2) ; apical edge of prosternum slightly emarginate; size 
smaller, length usually less than 1 mm.; eastern North America. 
M. depress, us LeConte 
— Sides of pronotum abruptly converging near apex, so that the 
lateral edge is more angulate; lateral lines of mesosternum con- 
verging from base to apex, each line posteriorly forming a wider 
angle (about 150°) with the metasternal line (fig. 3) ; apical 
edge of prosternum more deeply emarginate; size larger, length 
usually more than 1 mm. ; Arizona and northern Mexico. 
M. arizonensis , n. sp. 
