StaplnjlinidcB of the Amazon Valley. 339 



long spine or seta. I have not, however, made any 

 alhision to this in my description, for I am not at all clear 

 that this character is more than illusory. It appears to 

 me probable that the apex of the antennae is formed by a 

 projecting membrane which bears the spine, and that the 

 membrane can be retracted, in which case the spine dis- 

 a])pears, and the extremity of the antenna is apparently 

 truncate. 



1. Q^dichirus optatus, n. sp. Piceus, antennis, palpis, 

 pedibusque testaceis ; elytris thorace fere duplo breviori- 

 bus, basi valde angustatis; abdomine magno. Long. corp. 

 4ilin. 



]\Ias : abdomine segmento 7° ventrali medio profuude 

 angustius exciso. 



Antennas yellow ; 1^ lin. in length, 2nd and 3rd joints 

 about equal. Palpi and mandibles yellow. Head broad 

 and short, the front half bearing ten or twelve coarse 

 punctures ; the clypeus in front smooth, the vertex with a 

 few coarse punctures on each side ; the hind part bounded 

 on either side by a slightly raised carina. Thorax fully 

 I lin. in length, and about f in its greatest width, very 

 much narrowed behind, of a shining pitchy colour like 

 the head ; the sides in front greatly deflexed, the surface 

 bearing very coarse punctures, consisting of two irregular 

 rows of about a dozen punctures each along the middle, 

 these rows separated on the basal portion by a broad 

 smooth space, but on the anterior portion between them 

 about five coarse punctures on each side, so as to occupy 

 there the middle space ; near each side is a shorter row 

 of ]nmctures divergent towards the front ; between this and 

 the middle three or four punctures in front of the middle, 

 and also with punctures along the base and margins. 

 Scutellum moderately large, smooth. Elytra, from the 

 apex of scutellum to extremity of suture, | lin. in length, 

 curved at the sides and much narrowed at the base, rather 

 paler-])itchy in colour than the thorax ; their hind angles 

 projecting a good deal behind, the surface bearing coarse 

 ill-defined punctures and a few long hairs. Hind body 

 ample, the segments coarsely punctured, the 6th and 7th 

 segments only obsoletely and sparingly punctured; the 

 surface is but little shining, the basal portion oi each 

 segment being coriaceous ; the punctures are quite irre- 

 gularly disposed. Ths legs are entirely pale yellow. 



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