NORTH AMERICAN COLEOPTERA. 219 



Dorsal series of punctures extremely irregular or confused, or the 

 thorax numerously or even densely punctured. 



The species of this group are of at least moderate size. They all 

 have the front tarsi dilated, more widely in the males. The last ventral 

 segment of the male is always emarginate, and in one species ( Lecontei) 

 the penultimate also to a slight degree. 



Some of the species have the head punctured beneath, a character not 

 observed outside of the present series. Several species exhibit decided 

 traces of the infra-orbital ridge to which 1 have already called attention 

 in the Tachyporini, it is best marked in Lecontei and aii'^ulentus, and 

 fades out so gradually in the other species that no use can be made of it 

 in the tables. 



The species are arranged with serpentinus at the head, as this seems 

 more closely related to the mass of preceding species. 



Two of the species of the present series {Jxiltlviorcusis and ajiiaih's) 

 are placed by Fauvel in the genus Hesperus. If this reference be cor- 

 rect, then that genus seems not to rest on any tenable basis. 



All the species of this group seem peculiar to our fauna. 



Thornx either parallel or narrowed behind, longer than wide 2. 



Thorax oval, distinctly narrowed in front, as wide as long 5. 



2. — Thorax with very few punctures, head oval, narrowed hehind the eyes, nearly 



smooth Ncrpeiitinus. 



Thorax nutneroiisly or even densely punctured ; heail transverse or quadrate, 



not narrowed behind 3. 



3. — Thorax with numerous coarse punctures 4. 



Thorax densely punctured, except at middle fi. 



4. — Head transverse, wider than long. 



Antennae inoniliform ; elytra red ; abdomen brown baltiiliorensis. 



Antennre of normal f<irm, tip of abdomen rufe.scent apicalis. 



Head quadrangular. 



Legspiceous: head smooth beneath qiiailrilliis. 



Legs pale testaceous; head punctured beneath viridailUS. 



5. — Thorax very densely punctured, a narrow smooth space only ; legs pale testa- 

 ceous conrertiis. 



Thorax coarsely sparsely punctured ; legs piceous. 



Last ventral of male deeply triangularly emarginate, the j)enuhimate 



slightly emarginate; anterior tarsi patellate.. Eiecontei. 



Last ventral of male feebly emarginate,' penultimate entire; anteiior tarsi 



broadly dilated aiirnleiitiis. 



f). — Species very sMuiH and narrow piger. 



P. serpentinus n. sp. — Slender elongate, reddish brown ; elytra i)aler 

 liead and th.^rax iihick ; legs rufo-testaceous ; antennae nearly as long as the head 

 and thorax, piceous, the last two joints yellow, joints 7-10 as wide as long: liead 



