254 COLEOPTERA OF NORTH AMERICA. 



Mesosternum narrow, separating the coxae ; side pieces not 

 extending to the cavities. 



Metasternuni long, side pieces not very narrow ; epimera 

 visible. 



Elytra covering the abdomen ; epipleurae narrow, distinct. 



Abdomen with five free ventral segments ; the anterior 

 two of which appear more closely connected ; intercoxal 

 process acute. 



Legs slender ; anterior coxae small, conical, contiguous, 

 without trochantin ; middle coxae small, rounded, separated, 

 entirely inclosed by the sterna; hind coxae transverse, sepa- 

 rated ; tibial spurs small ; front and middle tarsi 5 -join ted ; 

 hind tarsi 4-jointed; the penultimate joint dilated into a 

 short membranous lobe beneath ; claws armed with a broad 

 basal tooth. 



The two genera which I have here associated have very few 

 points in common, except those above detailed ; the first resembles 

 in form some of the smaller Alleculae or Cisteloe, while the second 

 does not resemble especially any other insect known to me. 



The two genera indicate different tribes : — 



Head prolonged into a rostrum. Mycterini. 



Head short, not rostrated. Lacconotini. 



Tribe I.— MYCTERINI. 



Head prolonged before the eyes into a flattened beak as long 

 as the rest of the head : antennas nearly filiform ; epipleurae ex- 

 tending to the tip of the elytra ; first ventral segment as long as 

 the 2d ; 5th very short. 



The genus Mycterus, usually classed among Oedemeridae, alone 

 represents this tribe ; one species in the Atlantic States, and ano- 

 ther in New Mexico belong to our fauna. The firmer consistence 

 of the integuments, the distinct epipleuras, the small size of the 

 coxae, and the membranous sole of the penultimate joint of the 

 tarsi are valid reasons for removing this genus from association 

 with Oedemeridae to the position here given it ; the resemblance 

 in form to some of the members of Cistelidae is considerable, 

 while in structural characters, Mycterus has much affinity with 

 Salpingus. 



Tribe II.— LACCOJVOTINI. 



Head short ; antennas as long as the head and thorax, subser- 

 rate ; epipleurae not extending to the tip of the elytra ; first ven- 



