NORTH AMERICAN COLEOPTERA. 189 



Male. — Anterior tarsi rather broadly dilated ; last ventral segment deeply and 

 acutely triangularly incised. 



Female. — Anterior tarsi slightly dilated ; last ventral entire. 



As in all the small brown species the color varies from brownish testa- 

 ceous to piceous. The head is always black. The elytra often with the 

 sides, apex and suture paler than the disc. The ventral segments have 

 the apical border always paler ; even in the darker specimens the legs, 

 including the coxfe, are pale yellowish testaceous. 



This species, next to thermarum., is the smallest in our fauna with the 

 male tarsi dilated. 



Occurs everywhere in our fauna, including California, Nevada and 

 Arizona. 



The series here aggregated consists of species in which the anterior 

 tarsi of the male are dilated, and the thorax with a dorsal series of four 

 punctures. 



As will be seen by the characters used in the following table, the an- 

 terior tarsi of the male vary in the degree of dilatation. In a few the 

 tarsi are only moderately dilated, that is to say the male tarsi are not very 

 much broader than in the female. In others the tarsi of the male are 

 twice as wide as in the female, while in a few the anterior tarsi are patel- 

 late, forming a disc, as broad as long, composed of the first three joints. 



A few species have slender antennae ; in the majority the antennae are 

 not quite as long as the head and thorax, with the joints 5-10 nearly 

 square. 



The sexual characters of the male at the extremity of the abdomen 

 require special attention in the separation or species. \n grandicollis the 

 penultimate segment is also notched at middle, a very rare character, 

 otherwise known to me only in (tliininus, a species of the next division. 

 Two species, — Tlievencti and quadricollis, have the last ventral segment 

 longitudinally impressed in addition to the usual emargination. The 

 other characters used in the table do not need further explanation. It is 

 to be regretted that sexual characters have to be used in the table to such 

 an extent, but some of the species absolutely refuse to be separated in 

 any other describable manner. 



Anterior tarsi of males very broadly dilated, sometimes patellate ,2- 



Anterior tarsi of males moderately dilated, sometimes very little wider than in 



the female 3. 



2.— Thorax oval, very obviously narrowed in front. 



Elytra densely, finely punctured ; punctures of thoracic scries fine. 



gracilicornis. 

 (48J 



