418 SERBICOKNIA. 



4. Cardiophorus mexicanus. 



Moderately elongate, rather convex, slightly shining ; brassy black, the elytra pitchy-brown, with the suture 

 and sides castaneous ; the antennas black, with the basal joint reddish at the tip ; the legs piceous, with 

 the base of the femora, the knees, and the tarsi paler; the under surface black; above and beneath 

 thickly clothed with short, fine, cinereous pubescence. Head very closely, finely punctate ; antennas 

 slender, short, extending a little beyond the humeri, joints 3 and 4 subequal, 3 much longer than 2. 

 Prothorax convex, slightly broader than long, rounded at the sides, narrowed in front and behind ; the 

 hind angles moderately produced, not divergent, with a short faint lateral carina; the surface very closely 

 and finely punctured throughout ; the base feebly incised on either side. Elytra moderately elongate, 

 slightly narrowed in front, and there scarcely wider than the base of the prothorax, and narrowing from 

 a little beyond the middle to the apex, somewhat acuminate behind; finely and shallowly punctate- 

 striate, the punctures not very closely placed, the interstices almost flat, thickly and very minutely punctate. 

 Beneath very closely and finely punctured ; the propleurse separated from the pronotum at some distance 

 from the margin by a very faint carina which extends three-fourths the length of the prothorax. Claws 

 simple. 



Length 7|> breadth 2| millim. (6 •) 



Hob. Mexico, Jalapa (Edge). 



One example. Allied to C. floridce, Cand., from which it differs in having the 

 thorax shorter and more rounded at the sides, and the elytra very finely punctate- 

 striate, with the interstices almost flat. 



APTOPUS. 



Aptopus, Eschseholtz, in Thon's Archiv, ii. 1, p. 32 (1829) (part.) ; Candeze, Monogr. Elat. iii. 

 p. 230 * 



Aptopus, which may be easily known from its allies by the strongly pectinate tarsal 

 claws, is one of the most characteristic genera of Elateridse in Mexico, extending north- 

 wards to Texas and southwards to Brazil. With one exception, the species are all 

 American. It agrees with Cardiophorus in having the carina separating the pronotum 

 from the propleurae placed beneath and abbreviated in front. The Central- American 

 species, which all belong to Dr. Candeze's Sect. I., appear to be in a plastic condition, 

 and they are very difficult to distinguish. A. lateralis, Er., is one of the most variable 

 Elaterids known to me. 



a. Prothorax with more or less distinct intermixed larger punctures. 



a!. Hind angles not or feebly divergent Species 1-8. 



b'. Hind angles divergent Species 9. 



b. Prothorax without intermixed larger punctures. 

 cf. Hind angles not or feebly divergent. 



a". Body moderately elongate Species 10-12. 



b". Body elongate Species ] 3. 



d'. Hind angles distinctly divergent ; body elongate, narrow Species 14. 



* The typical species briefly described by Eschscholtz, A. cphippiger, from Bahia, and A. tibialis, from 

 Brazil, are not mentioned by Candeze. 



