PRIOCHIRUS.—MEGARTHRUS. 743 
duobus brevibus, parallelis, apice externo subtus dentato-producto, facie inferiore medio longius dentata, 
inter cornua area concava, profunde depressa. 
Long. 7-8 millim. 
Hab. Guatemaua, Volcan de Fuego 6400 feet (Salvin), Quiche Mountains 7000 to 
9000 feet, Cerro Zunil, Calderas 7000 feet, Volcan de Agua 8500 to 10,500 feet, San 
Gerdénimo, Sabo (Champion). 
This species is quite similar in appearance to P. hemorrhous, though readily 
distinguished by the cephalic structure and by the channel on the thorax being more 
deeply depressed behind. The long tooth of the horns of the vertex is placed so 
completely on the underside that it is difficult to detect. We have received a good 
series of specimens of P. salvini, which, though varying a little in size and also in some 
other minute particulars, are evidently conspecific. The most important variation is 
the existence occasionally of a fovea on the upper surface of the head on each side 
of the median channel. 
Group PROTEININA. 
MEGARTHRUS. - 
Megarthrus, Stephens, Ill. Brit. Ent. v. p. 330 (1832); Erichson, Gen. et Spec. Staph. p. 904 (1840). 
This genus has hitherto consisted only of a few species found in the northern 
portions of the eastern and western hemispheres, extending, however, to Madeira and 
the Canary Islands. 
1. Megarthrus zunilensis. (Tab. XIX. fig. 15.) 
Fuscus ; antennarum articulis duobus ultimis testaceis; prothorace lateribus plus minusve distincte rufescen- 
tibus, ad angulos posteriores breviter latius excisis. 
Long. 3 millim. 
fab. Guatemata, Cerro Zunil (Champion). 
Antenne slender, the two terminal joints conspicuously paler than the others. Thorax 
densely punctate, with a broad channel along the middle, the lateral margins slightly 
angulate in the middle; the hind angles rectangular, slightly acute, and behind them 
a small excision broader than long. Elytra nearly twice as long as the thorax, very 
densely and finely punctured. Male with the hind and middle tibie rather thicker, and 
the terminal ventral plate largely and deeply excised. 
A distinct species, somewhat resembling the European J. sinuaticollis, but with 
different thoracic margin and remarkably coarse sculpture of the elytra. 
2. Megarthrus solitarius. 
Fusco-niger, opacus, fortiter punctatus; pedibus piceo-testaceis ; prothorace antrorsum angustato, lateribus 
undulatis, angulo posteriore acuto, retrorsum spectante. 
Long. 22 millim. 
Hab. Guaremata, Purula (Champion). 
