NORTH AMKKK'AN (X>LK()PTI-:RA. 3o 



The resenihltuice l)et\veeii thi;^ species and aurata is certainly very 

 great. When males are examined the group of punctures of the 

 presternum will readily separate it. In either sex it will be observed 

 that the hind angles are somewhat obtuse, while in auraia they are 

 sharply rectangular. The thorax is also shorter in the present 

 species. 



Occurs in California, Washington and Vancouver. 



Group musculus. 

 Antenna> and legs pale rufo-testaceous. Prosternum of male 

 without group of |)unctures, the tip with a marginal line, but without 

 setse. 



In this group it is proposed to unite the species separated by Zim- 

 mermann in his eighth and ninth groups, the distinction between 

 the two being that the former has the thorax square, the latter nar- 

 rowed in front. This distinction is so purely specific, and among 

 our species not readily appreciable, that for convenience it is thought 

 better to treat the groups as one. 



The males have the anterior tarsi dilated in the usual manner 

 and the last ventral segment one marginal seta each side, the females 

 have two. 



In none of the species are the sides at all deplanate, resembling in 

 this respect the gibba group. One species only has a decided metallic 

 lustre, the tendency being rather to castaneous or piceo-testaceous. 

 The species are not difficult to separate by comparison, l)ut more 

 troublesome to distinguish by description. 



The following table will be of assistance : 

 Siii-face shining, rather conspicuously metallic. 



Slriie not punctate; frontal impressions distinct illirata. 



Surface piceous to rufo-testaceous, without any well marked surface lustre. 



.Sides of thorax oblique behind tlie middle, hind angles sharply rectangular; 

 scutellar stria united at base with the second and at its ai>cx with 



the first stria har|u»Iiiia. 



Sides of thorax not oblique beliind the middle, usually arcuate from the 

 hind angles; scutellar stria always free at its apical extremity. 

 Thorax distinctly emarginate at apex, the angles sharply prominent to the 

 front, hind angles rectangular; elytral stripe punctulate..sub«'ii<'a. 

 Thorax almost truncate at apex, anterior angles very obtuse. 

 Elytral stria' distinctly punctulate. 



Form more oblong, hind angles of thorax much rounded: metnstcr- 



num at sides and metepistcrna coarsely punctate riibrica. 



Form more oval, hind angles subrectangular or obtuse, not rounded; 



metasteruum and metepistcrna smooth — iiiiimciiIiim. 



Elytral stria' not punctulate: metasternum ;ind nietepisterna smooth. 



t(M;aiia. 



TR.\NS. AM. KNT. SOC. XIX. ..MARCH, 189J. 



