188 BULLETIN 46, UNITED STATES NATIONAL MUSEUM. 



moderately ovate, the first four dorsal plates smaller than the succeed- 

 ing-. Anal segment large, not tuberculate, inclosed between the lateral 

 carinaB of penultimate; anal valves smooth ; anal scale absent. Lateral 

 cariure large, angulated; the fifth deeply emarginate, bilobed. Repug- 

 natorial pores born on a pedicel, placed on the anterior lobe of fifth 

 lateral cariure, but supapical on the rest. Legs extending beyond sides 

 of body. 



Androynathus is closely allied to the European genus Dolistenus 

 Fanzago, but the later genus is separated from Andrognatlms by the 

 form of the fifth segment and of the repugnatorial pores. 



This genus contains the following species : 



Andrognathus corticarius. 



Andrognatlius corticarius Cope. Proc. Amer. Phil. Soc., 182, 1869 (Montgomery Co., Fa.) ; 

 Boilmau, Aim. N. Y. Acad. Sci., 108, 1888 (Bearer Cr., Tenn.). 



Yellowish brown, legs and under parts paler. Segments 40-60, first 

 four smaller than the succeeding. Lateral carinse strongly developed, 

 more aliform posteriorly. Repugnatorial pore large, placed on the 

 anterior lobe of fifth segment, but posterior and almost subapieal on 

 the others. Male: Anterior legs with claws normal. Length of body 

 10-20 mm . 



Habitat. Montgomery Co., Va. (Cope); Mossy Creek, Strawberry 

 Plains, and Beaver Creek, Jefferson County, Tennessee. 



PLATYDESMUS. 



1843. Phiti/desmus Lucas. Ann. Soc. Ent. France, 51 (polydesmoides). 

 1849. Piestodesmus Lucas. Rev. et M:i-. Zool., 589 (inort'leti). 

 l$6i.Brachycybe Wood. Proc. Phila. Acad. Nat. Sci., 187 (lecontei). 



Body wide depressed, elongate-oblong, covered with numerous short 

 hairs; convex above and below. Head not suctatorial nor concealed 

 by the first dorsal plate, densely pilose. Antennae slightly clavate, 

 second article longest, bases remote. Ocelli absent, Mandibles small, 

 triangular, two-toothed and pilose on the inner side. 



Gnathochilarium well developed; stipes large, mala and teeth not 

 well developed; hypostoma as in Pseudoflesmns; cardo present; men- 

 turn hammer-shaped; promeu turn small, elongate orate; lingual plates 

 touching, lingual lobes distinct. Dorsal plates uiedianly sulcate, with 

 two transverse rows of non-pilose tubercles. Lateral carino? large, 

 those of the first ten directed forwards. Anal segment tuberculate, 

 included between the lateral carinai of penultimate ; anal valves smooth ; 

 anal scale present. Repuguatorial pore beginning at fifth segment, and 

 nearer the anterior margin than the others. Legs not extending beyond 

 sides of body. 



Platydesmus, Piestodesmus, and P>racliycybe agree in all points except 

 as to the possession of ocelli Piestodesmus has two, Platydesmus one, 



