STUDIES OF THE MEXICAN SUBGENUS PLATYNELLA 
CASEY (COLEOPTERA: CARABIDAE: AGONINI) 1 
By Thomas C. Barr, Jr. 
Department of Zoology, University of Kentucky, Lexington 
Studies of the Mexican cave carabids of the genus Mexisphodrus 
(Barr, 1965, 1966) led me to a comparison of its species with Boli- 
varidius , described as a genus of sphodrines by Straneo (1957), and 
Platynella , described as a subgenus of Anchomenus by Casey (1920). 
It is probable that neither Bolivaridius nor Mexisphodrus are “true” 
sphodrines in the final analysis, since both have the simple right para- 
mere of subtribe Agoni rather than the elongate ones characteristic 
of the European and Asiatic sphodrines. Mexisphodrus does have a 
sharply truncate, triangular prosternal base similar to that of the 
sphodrines, but Bolivaridius does not. However, the truncate pro- 
sternum is also found in a number of other Mexican and Central 
American u Colpodes , \ and Mexisphodrus is perhaps best regarded as 
allied with other American species. 
Mexisphodrus tlamayaensis (Barr, 1966), a winged species with a 
predilection for caves (San Luis Potosi, Tamaulipas, Veracruz), 
should probably be excluded from Mexisphodrus until a thorough 
study of the American colpodines has been made; it has the truncate 
prosternum and colpodine tarsi of Mexisphodrus but not the same 
habitus. Described as piceous in color, it acquires a dark, bluish-black 
pigment in some habitats, and is doubtless related to some of the 
species described as Colpodes by Chaudoir. 
Platynella and Bolivaridius share the same generally somber color, 
vestigial wings, and elongate, subconvex form of Mexisphodrus , but 
lack the truncate prosternum and the bilobed 4th metatarsal segment 
of the latter. The descriptions of these two groups are surprisingly 
similar, not only to each other but also to the description of Ancho- 
menus montezumae Bates (1878). Thanks to my colleague, Dr. 
Candido Bolivar y Pieltain, Instituto Politecnico Nacional, Mexico 
City, I was able to examine topotypes of Bolivaridius tolucensis and 
a paratype of B. ovatellus , and to compare them with two specimens 
of Anchomenus montezumae lent to me from the Biologia Centrali- 
Americana collection by Dr. R. B. Madge, Commonwealth Institute 
of Entomology, British Museum. Casey’s types and associated speci- 
This investigation was supported in part by a grant from the National 
Science Foundation (GB-5521). 
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