247 



The erratica group is spread widely over the subarctic parts of 

 the northern hemisphere; the strial intervals are usually somewhat 

 irregularly elevated, at least in part. The calif ornica group seems 

 to be confined to the western parts of North America, extending 

 southward through most of Mexico. The rectangula group com- 

 prises at present but a single peculiar species, confined to the Pacific 

 regions. The remotestriata group contains a great many usually 

 pallid species, of more or less robust form, widely distributed over 

 the northern hemisphere. The aurata and rubrica groups seem to 

 be peculiarly North American, the former confined to the Pacific, 

 the latter to the Altantic, regions; one species of the rubrica group 

 occurs in British Columbia and one each in Arizona and Chihuahua; 

 no species of the aurata group occurs far from the Pacific coast line. 



Group I 



The antennae in this group are black, as well as the legs, although 

 the antennal base is often paler in color. The species are rather 

 numerous, the group extending far into Mexico; those at hand may 

 be known as follows : 



Body stouter; head better developed, always at least somewhat more 



than half as wide as the prothorax 2 



Body narrower, the size smaller as a rule; head notably smaller, never 



more than half as wide as the prothorax in either sex 8 



2 Upper surface with pronounced metallic lustre 3 



Upper surface without metallic lustre 5 



3 Pronotum rather distinctly depressed externally toward base; strial 

 intervals remarkably irregular. Body oblong, very moderately con- 

 vex, rather shining, the elytra strongly alutaceous in the female; 

 color of the upper surface varying from bright bronze to dark green; 

 legs black, the femora faintly rufescent; head evenly convex, with 

 rather prominent eyes, the strides small, linear and oblique; anten- 

 nae black, slender, the two basal joints dark rufous; prothorax less 

 abbreviated than in the four following and three-fifths wider than 

 long, the sinuate apex much narrower than the base; stria very fine, 

 much abbreviated; surface with a feeble striiform impression at 

 basal third, nearer the middle than the sides and, nearer the angle, 

 one that is feeble and oblique; basal angles right, not blunt, the 

 puncture equidistant from base and side, the anterior puncture at 

 two-fifths from the blunt but prominent apical angles; elytra less 

 than one-half longer than wide, very slightly wider than the pro- 

 thorax, the sides feebly arcuate; apex ogivally lobed at the middle; 

 striae very fine, impunctate, the scutellar long, the lateral ocellate 

 series moderately interrupted; intervals alternately rather elevated 



