418 PROCEEDINGS OF THE NATIONAL MUSEUM vol. m 



Platydema ellipticum (Fabricius) 



Plate 5 (Fig. 37) 



Tenebrio ellipticus Fabricius, 1798, p. 49. 



Mycetophagus ellipticus Fabricius, 1801, p. 566. 



Platydema elliptica (Fabricius). — Laporte and Brulle, 1831, p. 380. — Candeze, 



1861, p. 46 (larva). 

 Platydema ellipticum (Fabricius).— Horn, 1870, p. 383. — Blatchley, 1910, p. 1263. 



Weiss, 1919, p. 276 [biology]. 



Description. — ^Elongate elliptical, moderately convex, dark browii 

 to black, with irregular reddish spot on each elytron, dull in lustre. 

 Head coarsely and densely punctured, epistomal suture clearly out- 

 Uned; eyes moderately large, broadly and deeply emarginate anteri- 

 orly; mouthparts and antennae dark brown to black, terminal seg- 

 ment of maxillary palpus robust, elongate oval, obliquely truncate 

 apically. Pronotum almost twice as broad as long, sides evenly 

 arcuate and rather strongly convergent from base to apex, apex 

 feebly emarginate, base slightly bisinuate, both basal and apical 

 angles sharply rectangular, lateral margms scarcely expanded, bead 

 very fine, surface coarsely and densely punctured, especially laterally. 

 Elytra with sides nearly parallel, narrowly margined, bead fine and 

 strongly reflected, striae shghtly or not at all impressed, finely and 

 distantly punctured, intervals subconvex to flat, minutely and sparsely 

 punctulate, surface black with a prominent, uTegularly margined red 

 spot extending obliquely from humeral region of each elytron toward 

 sutm-e, sometimes actually attaining it. Ventral surface of pronotum 

 coarsety and densely punctured, forming longitudinal ridges; pro- 

 sternal process horizontal, its apex prominent and acute posteriorly; 

 entire ventral surface dark brown or black, shining, coarsely and 

 densely punctured, punctures smaller and more widely separated on 

 apical two abdominal sternites. Male aedeagus with basal sclerite 

 robust and subequal in length to apical sclerite, which is parallel 

 sided and acutely pointed apically (pi. 5, fig. 37). Measurements: 

 length 4.4-7.7 mm.; width 2.3-3.S mm. 



Remarks. — This species is unique among the North American 

 components of the genus Platydema in having the distinct, constant 

 color pattern described above. From Central Mexico, south through 

 most of South America, a number of very similar species enter the 

 fauna. These consist of moderate to rather large forms, dull black 

 dorsally, attractively patterned with spots and bands in various 

 combinations and arrangements of this same reddish color noted in 

 P. ellipticum. A number of these have been studied and on the basis 



