NORTH AMERICAN COLEOPTERA. 



23' 



wide distribution, "presenting the phenonienon of races which 

 mic^ht be supposed to be distinct species if one studied with meagre 

 ma'terial To avoid error from the hitter cause it is well to collec 

 as laro-ely as possible from different broods in succeeding years and 

 'remot^ localities. When this is done it will be found that, while 

 there are geographical races, individuals will occur in broods repro- 

 ducing exactlv the usual type of the races from remote localities 



As this group is composed of those species remaining after all those 

 with well defined, usually structural, characters have been ren.oved 

 it- characters are more of a negative than positive character. 



Bodv not pubescent above, usually shining, in a few species prui- 

 nose «; iridescent. Antennae 10-jointed, the club of the male always 

 longer than that of the female. Clypeus usually emai^mate, al- 

 though at times feeblv. Last joint of maxillary palpi fusiform, 

 without impression. Thorax variable in form, the sides sometimes 

 subancndate, the margin often serrate or crenulate. Posterior tibi^ 

 truncate at apex, without trace of sinuation at the base of the fixed 

 sT^ur of the male; this^spur usually long, at most feebVj^ curved. 

 Claws strongly toothed at middle, the tooth of the male usua ly 

 .mailer than in the female. Posterior tarsi of female usually shorter 

 than in the male. Last ventral segment large in both sex es^ 



The homogeneity of the species renders it extremely diflficult to 

 separate them in tabular fi.rm by any characters suflicie.itly constant 

 or sharplv defined to make their recognition certain. The following 

 is the division proposed by Dr. LeConte, and has been adopted, al- 

 though son,e modification of the species admitted in each series has 

 been^made for reasons which will be explained. 

 Clypeus not densely punctured, the margin moderately relieved, feebly enu.rgin - 



ate- lateral margin of thorax not serrate, except in .,T«»....Species 4 3 

 Clypevl' densely punctured, the margin at most narrowly reflexed, moderately 

 '^'^cirirel'rg'inate; thorax not angulate at the sides, t^e lateral mar^n 



Cly;;::::irr;r;dingTti;o;a; ;;;;;nguiat;;t the-^ld^s. .^aHy narrower 

 '^t base than at middle, the margin always more or less serrate.^^^^^ ^^_^^ 



Species 24—32. 

 In this series the punctures of the clypeus are well separated and 

 not crowded together, the clypeus is more or less concave, the mar- 

 gin moderately or even widely reflexed, the emargination always 

 feeble The thorax is narrowed from the base, when viewed from 



