294 G. H. HORN, M D. 



This is our largest species aud is more deeply striate than auy other 

 in our fauna. 



Collected in the Lake Superior region. 



M. crassa,, Lee. Pacif. R. R. Rept. App. I, p. — Black, shining, form robust, 

 elongate oval. Head entirely verriieose, clypeus feebly emarginute. Tiiorax 

 short, more than twice as wide as long, sides rounded narrowing to the front, 

 surface with coarse punctures at middle basal region, smoother and less punc- 

 tured at the sides and anteriorly and with a shallow impression at the hind 

 angles. Elytra very convex, one half longer than wide, strife not deep, moder- 

 ately and rather distantly punctured; intervals flat impunctured. Hind tibise 

 stout, spurs moderately thick, curved, and obtuse at apex. Length .16 — .18 

 inch ; 4 — 4.5 mm. 



Occurs rather abundantly on the sea coast south of San Francisco, 

 California. 



IE. conferta, n. sp.^ — Oblong, black, shining. Head rather densely verrucose, 

 clypeus feebly emarginate. Thorax one half broader than long, sides rounded 

 and narrowed in front, surface, coarsely punctured on the disc at the sides 

 smoother, with a rounded impression and a slight transverse impression near 

 the anterior angles. Elytra broader behind the middle, deeply striate, striae 

 punctured; intervals convex smooth. Legs piceo-rufous, hind tibiae stout, 

 spurs broad, leaflike at the apical half, hind femora with an entire sub-mar- 

 ginal row of setigerous punctures Length .14 — 18 inch; 3.5 — 4.5 mm. 



This species is similar in form and appearance to lacustris, but may 

 easily be known especially by the form of the binder tibial spurs. 

 Occurs rarely in the Middle and Southern States and in Illinois. 

 Having thus far disposed of all the species known to me as inhabit- 

 ing our fauna the following table and remarks are presented as afford- 

 ing ready means of determining the genera. 



Mandibles visible beyond the clypeus .ffigialia. 



Mandibles entirely concealed beneath the clypeus. 



Hind tarsi with triangular joints Fsaminodius. 



Hind tarsi with elongate joints, usually cylindrical. 

 Head as])erato-granulate or verrucose. 



Thorax not fimbriate; grooves short lateral Pleurophorus. 



Thorax with scale like marginal hairs; grooves entire Bhyssemas. 



Head punctured or slightly plicate. 



Thorax broader at base than elytra, hind tibiae spiniform at 



apex Euparia. 



Thorax never broader than elytra. 



Outer apical angle prolonged spiniform Ataenius. 



Outer apical angle of hind tibiae obtuse. 



Anterior tibiae with upper teeth obsolete, the terminal tooth 



anterior Dialytes. 



Anterior tibiae strongly toothed, teeth external. 



Elytra with costiform intervals Oxyomus. 



Elytra simply striate Aphodius. 



The first three genera have the maxillae corneous and with a hook 



