144 MEMOIRS ON THE COLEOPTERA 



Group XIII sphceroderum 

 Subgenus Cyclolopha nov. 



Species resembling the singular Bembidion sph&roderum, described 

 by Mr. Bates from Mexico (Biol. C.-A., I, i, 1882, p. 147), occur in 

 Arizona and New Mexico, but appear to have been unknown to 

 our earlier reviewers. In their small, oblong-oval, convex body and 

 virtual absence of posterior thoracic angles, they suggest somewhat 

 the European subgenus Philochthus, but on comparison with Phi- 

 lochthus guttula and biguttatus Fabr., as depicted by Duval, they 

 are seen at once to differ in the very much more obliterated hind 

 angles of the prothorax, and also in the presence of a coarsely beaded 

 margin along the thoracic base, in which they resemble Lopha more 

 than they do Philochthus, and, as further proof of this relationship, 

 Mr. Bates has described Mexican species, such as cyclodes, with 

 elytral maculation resembling somewhat that seen in Lopha quadri- 

 maculata. Cyclolopha may be regarded, however, as the American 

 analogue of Philochthus. The four species at hand may be de- 

 scribed as follows : 



Elytra oblong, with parallel, feebly arcuate sides 2 



Elytra oval, with strongly arcuate sides 3 



2 Form parallel, moderately convex, highly polished and black through- 

 out above, without metallic lustre; under surface piceous, the in- 

 flexed sides and legs rufous; head two-thirds as wide as the prothorax, 

 with moderate, prominent eyes and narrow, slightly converging 

 sulci; antennae moderately slender, two-thirds as long as the elytra, 

 fuscous, gradually testaceous basally, the medial joints slightly more 

 than twice as long as wide; prothorax nearly four-fifths wider than 

 long, the sides subparallel, almost evenly, moderately rounded and 

 well reflexed, rounding rapidly at base and obliquely arcuate thence 

 to the thoracic pedicel, which is strongly beaded and one-half the 

 maximum width; the hind angles can barely be traced by the pos- 

 terior setigerous fovea on the upturned edge; impressions obsolete, 

 the stria excessively fine, subobsolete; foveae very small, smooth, 

 moderately deep, at the obtuse angle between the base and the ob- 

 liquely arcuate sides adjoining; there is no trace of a carina; elytra 

 three-fifths longer than wide, only a fourth or fifth wider than the 

 prothorax, parallel, the sides rapidly rounding at the humeri; apex 

 gradually parabolic; striae extremely fine, unimpressed, obsolete be- 

 hind the middle laterally and in posterior third inwardly, only the 

 sutural entire, deep and groove-like; seventh stria completely want- 

 ing; punctures minute, feeble; foveae near basal fourth and apical 

 third, the anterior very close to the third stria, the other medial on 

 the interval. Length (cf ) 3.6 mm.; width 1.3 mm. Arizona (Grand 

 Canon of the Colorado), T. Mitchell Prudden occultum n. sp. 



