312 LAMELLICOENIA. 



and the broadly rounded mandibles the species closely resembles D. dubius. The 

 closely sculptured pygidium led Burmeister to confuse it with the North-American 

 D. trachypygus ; this latter is smaller and more ovate in form, more strongly pnnctate, 

 and has the pygidium still more densely sculptured and opaque and in the female 

 furnished with two polished callosities near the apex ; in D. Icevipunctatus the sculpture 

 of the pygidium is not so dense and leaves narrow smooth elevated interspaces. 



The claw-joint of the anterior tarsi in the male is slender and straight as in the 

 female, with level under surface, and the larger claw is scarcely thickened and forked ; 

 in D. trachypygus it is much thickened and strongly sinuated underneath, with long 

 and thick much deflected larger claw. 



Two allied species (D. dubius and another undescribed) similarly differentiated in the 

 males are found together also on the Lower Amazons, and I at first thought they were 

 cases of dimorphism in the male ; but the differences in the male claws are associated 

 with other differences in the form and sculpture of the pygidium. In D. Icevipunctatus 

 the pygidium is scarcely convex even in the male ; in the following species it is rather 

 strongly convex in this sex and triangular, but has compressed sides in the female. 



I have adopted the MS. name given to the species by Chevrolat in the Salle col- 

 lection. 



2. Dyscinetus frater. (Tab. xvm. fig. 13, s .) 



D. Icevipunctato simillinms, elongato-oblongus, postiee vix dilatatus, niger, clypeo plerumque fere laevi, antice 

 lato margineque acute (nee in medio altius) reflexo, fronte pauciter punctulata ; thoraee passim distanter 

 et mediocriter punctate- ; elytris utrinque striis geminatis punctulatis vix impressis, costulis quatuor 

 planis, interspatiis plerumque sparse punctulatis. 



J 1 . Pygidium crebre confluenter punctulatum, medio versus apicem laeve politum. Tarsi antici articulo 

 unguiculari robusto, subtus sat profunde sinuate-, ungue majore latissimo, deflexo, insequaliter fisso. 



§ . Pygidium triangulare, parum convexum, sparse punctatum, nitidum, basi crebre confluenter punctatum. 



Long. 20 millim. <S $ . 



Hab. Mexico, Paso del Macho, Paso de San Juan in Vera Cruz, Tejeria (Edge). 



3. Dyscinetus picipes. 



Chalepus picipes, Burm. Handb. der Ent. v. p. 79 \ 



Hab. Mexico, Cordova, Toxpam (Salle), Jalapa, Toluca, Vera Cruz, Tejeria (Edge). — 

 West Indies \ Cuba, Santo Domingo, Guadaloupe. 



The strong and separated punctuation of the pygidium in both sexes mentioned by 

 Burmeister is very constant ; but a more important specific character is the very robust 

 anterior tarsi of the male, the fourth joint of which is prolonged at the apex beneath 

 (the prolongation finely striated) and the claw-joint strongly sinuated on its under 

 surface, with the major claw remarkably broad, deflected, and unequally cleft, and the 

 slender division divergent. The clypeus is always undulate-strigose and much narrower 

 in front than in the preceding species, with its reflexed margin higher and sometimes 



