103 



Junexgoc] CaSEY : On NORTH AMERICAN COLEOPTERA. 



course that the female has these tarsi 5 Jointed. In each case the three 

 basal joints are short, stout and equal and together scarcely longer 



than the last. 



Atomariin.e. 



The genera of this subfamily may be readily recognized by the palpal 

 structui^e and position of the antennce, these organs being inserted 

 upon the front and more or less approximate at base, the fovese being 

 either small and exposed or deep cavities, separated above by a short 

 an-ular extension of the upper surface, and particularly developed m 

 clwscelis and Stcrnodea. The tarsi are always slender and filiform, 

 as in the Crvptophagini, of the preceding subfamily, and. as m that 

 case there is frequently a feeble thickening of the anterior in the 

 males The body is much smaller as a rule than in the Cryptopha- 

 ciriK and may be either narrow and parallel, as in Agathengis, or oval 

 and more convex, as in the great majority of genera. The subfamily 

 may be resolved into the four following rather widely differentiated 



tribes : — 



Prosternal process free, the tip passing ova. the flat or feebly concave surface of the 

 mesosternum; antennc. free, the grooves before the eyes wholy obsolete, he 

 club loosely 3-jointed ; basal segment of the abdomen not modihed behmd the 



coxae except in Tisactia ; 



Prosternal process broader and flatter, generally prominent, forming a contn.uous sur- 

 face with the mesosternum, its tip broadly arcuate and received closely withm a 

 corresponding depression at the apex of the mesosternum ; body more compact, 

 the prothorax more closely fitted to the elytra ; buccal processes obsolete ; elytra 



never margined at base ; tarsi pentamerous - ••••••3 



.-Prosternal process prolonged and acute at tip, the mesosternum concave ; prothorax 

 with a double lateral margin ; tarsi pentamerous in the female and heteromerous 

 in the male ; first abdominal segment well developed, longer than the next two 

 combined, the sutures bent strongly backward for a short distance at the sides ; 

 antennal cavities large, narrowly separated; buccal processes long and promi- 

 nent, the eyes very coarsely faceted ; body elongate, only moderately convex, 



generally coarsely sculptured and sparsely pubescent C.enoscelini 



Prosternal process shorter and truncate, the mesosternal surface generally flat ; pro- 

 thorax with a fine single lateral edge ; tarsi pentamerous in both sexes ; abdominal 

 sutures straight throughout the width ; antennal cavities small and superficial, the 

 buccal processes extremely short and inconspicuous, the eyes much less coarsely 



faceted ; body variable in form, sculpture and vestiture AtomaRUM 



._\ntenm^ free, the club 2-jointed in Stcrnodea, the cavities very large and deep 

 'contiguous; first ventral segment as long as the next three combined, without 

 post-coxal plates, the sutures broadly, feebly reflexed toward the sides; proster- 

 num extremely prominent along the middle, with acute lateral margins extend 

 ing to the anterior margin ; tibi. feebly claviform ; scutellum -U developed and 

 transverse ; anterior coxa; almost rounded 



