ALASTOR. 317 



Form slender and cylindrical. Forehead rather tumefied, 

 parted by an obsolete groove ; between the antennae a vertical 

 carina. Thorax much arched above, anteriorly. Prothorax 

 rather concavely cut anteriorly, its margin hemmed ; the hem 

 forming a right angle on each side, along the lateral margin; the 

 angles lamellate, inferiorly excavated. Scutel flattened, included 

 behind by the metathorax, which is narrower than the rest of 

 thorax, cylindrical or rather truncate-conical, being slightly 

 narrowed posteriorly, much produced behind the post-scutel and 

 sharply truncate vertically, and parted by a groove superiorly. 

 Its posterior face circular, strongly, spherically excavated, smooth 

 and finely punctured, parted by a fine groove ; its superior and 

 lateral margins forming together a sharp edge in the form of a 

 very regular circle, not complete inferiorly and notched superiorly 

 by a fissure ; this sharp circular edge slightly reflexed in a sort 

 of crest, but not crenulate ; the inferior margins oblique, making 

 by their conjunction with the circular margin on each side a 

 lateral tooth, often notched so as to form a second inferior angle. 1 



Abdomen elongate, cylindrical, quite sessile. First segment a 

 little narrower than the second, rather elongate, very sharply 

 truncate anteriorly, fitting into the concavity of the metathorax. 



Head and thorax coarsely punctured ; the metathorax very 

 coarsely ; abdomen quite finely and shallowly punctured ; the 

 second segment quite obsoletely channelled near its posterior 

 margin, but not rugose. 



Quite black; feet rather silky with fulvous reflections. Wings 

 black, violaceous. 



9 . Clypeus polished, very coarsely cribrose, widely emarginate 

 at the extremity, rather bidentate; the teeth subcarinate. 



Bess. a. diff. — Very closely allied to A.singularis. ■ 



Hab. Brazil (type in the author's collection). 



Observation. — I first characterized this species as having its 

 metathorax quadridentate, but the teeth in the lower part of 

 metathorax are often obsolete, so that it is sometimes only 

 bidentate. 



5. A. Singlllaris Sauss. — Niger, capite et thorace crasse punctatis ; 

 A. mrlanosomce affinissimus, at clypeo 9 latiore quam longiore, apice 

 truncato, baud emarginato ; metanoti cantho acuto, orbiculari, infra 



1 Notched on one side and not on the other, in one specimen. 



