SCARABiElDAE. 25T 



But two groups are found in our country, and in both the 

 labrum is horizontal, short, and sinuate, and the mentuni quadrate. 



Elytra with a meuibranous margin. Anomaly. 



Elytra without membranous margin. Rl'tel^^e. 



Group I. — Anomalae. 



These insects are of small size, have 9-jointed antennae, and the 

 mandibles in repose do not project beyond the clypeus. Only 

 two geuera occur in our fauna, and neither has yet been found on 

 the maritime Pacific slope of the continent. One of the anterior 

 and middle claws is cleft in all the species, except A. cuvifrona. 



A. Epimei'a of the mesothorax inferior ; elytra not emarginate at base ; 



Presternum not prominent behind the coxae ; clypeus parabolic. 



Anomala. 



B. Epimera of the mesothorax ascending ; elytra emarginate at base ; 



Clypeus parabolic; prothorax sulcate or impressed. Strigoderrua. 



The species of the last-named genus have the elytra flattened 

 and deeply sulcate; but three are included in our territory. 



Group II. — Rutelae. 



Insects of moderately large size, having 10-jointed antenna?, 

 and prominent mandibles. Our genera belong to three sub- 

 groups, Pelidnotae, Areodse, and Rutela?; they may be tabulated 

 thus, all of our species, except Pohjmcechus hrevipes, which is 

 allied to Parastasia, having entire simple claws : — 



Thorax margined at base ; 



Clypeus united with the front without sutufe. Pelidnot.-e. 



Mandibles emarginate or bidentate externally. Pelidnota, 



Mandibles entire. Plusiotis. 



Clypeus distinctly separated from the front. Akeop.-t.;. 



Last tarsal joint not prolonged beneath. Cotalpa. 



Thorax not margined at base. Rutel.t^;. 



Claws entire; clypeus not reflexed. Rutela. 



Claws in part toothed ; clypeus reflexed and bidentate. Polymoechus. 



Tribe II.— DYNASTI^I. 



Insensible transitions through foreign genera connect closely 

 this tribe with the preceding, but those found in our fauna will 

 not produce much difficulty in the mind of the student. 



The mentum is usually narrowed and subacuminate in front, 



n 



