138 COLEOPTERA OF NOKTH AMERICA. 



Group II. — Cryptophagi. 



Small insects, of an elongated form, living in decomposing 

 vegetable matter; usually of a brown color, and clothed with 

 rather coarse hair. The sides of tlie thora.x are usually toothed. 

 The prosternum is slightly prolonged, but the mesosternum is not 

 emarginate for its reception. The antennae and front are alike 

 in both sexes, and the latter is somewhat prolonged. 



The. posterior tarsi of the male in our genera have but four 

 joints. 



Thorax emarginate at apex ; surface glabrous. Emphylus. 



Thorax truncate at apex and base ; surface pubescent. 



Front finely margined over the base of the antennae ; fourth joint of tarsi 

 short. Henoticus. 



Front not margined ; fourth joint nearly as long as the first. 



Cryptophagus. 



Tribe III.— ATOMARIIKI. 



The antennae are inserted between the eyes, at the anterior part 

 of the front, and are usually very closely approximated. The 

 mentum is tridentate in front. The anterior coxae are rounded. 

 The tarsi are not lobed beneath; the fourth joint is smaller than 

 the third. The species are of very small size, and are found 

 flying in the evening, and about wood-piles. The two groups of 

 Atomaria recognized by previous authors have been separated 

 as genera by lleitter. 



Posterior tarsi of male 4-jointed ; form elongate, pubescent. Caenoscelis. 

 Posterior tarsi of both sexes 5-jointed. 



Oblong or oval ; pubescent. Atomaria. 



Ovate, glabrous ; prosternum broad. Ephistemus. 



Fam. XXYIL— mycetophagidae. 



Mentum transverse, trapezoidal; ligula usually corneous, 

 without paraglossse; labial palpi 3-joiuted. 



Maxillas with two lobes, ciliate at the extremity; maxil- 

 lary palpi 4-jointed. 



Eyes tolerably large, transverse or rounded, strongly 

 granulated. 



Antennse inserted immediately in front of the eyes, 11- 

 jointed, the outer joints gradually or suddenly enlarged. 



