291 
of the Amazon Valley. 
2. Octoplon polyzonum, n. sp. 
Linear, head and thorax black, the latter very uneven, 
with the front and hind parts and sides very densely 
clothed with white tomentum, leaving an opaque por» 
tion in the middle, and two posterior tubercles black. 
Elytra pale tawny-brown, with five dark brown belts, 
the first very oblique near the shoulder, the second 
also oblique, much dilated towards the sutural end near 
the scutellum, the third straight, linear, and entire be- 
hind the middle, the fourth a little posterior to the third, 
much broader, rather paler and slightly oblique, and 
the fifth transverse, near the tip ; behind the fifth belt, 
the elytra are testaceous-white, and between the third 
and fourth pale tawny; the surface is shining and im- 
punctate, except a few setiferous punctures arranged in 
rows. Legs testaceous- tawny, hind thighs rather longer 
than the elytra, gradually but rather considerably thick- 
ened, the tips with two equal projecting broad spines. 
Long. lin. ( $ ?, third joint of antennae not thick- 
ened) . 
Hah . — Eiver Tapajos. The fourth antennal joint is 
much shorter than the preceding and following. 
3. Octoplon tetrops, n. sp. 
Angustatum, thorace antice attenuato et constricto, 
capite valde exserto, collo distincto, rufo-testaceum ; capite 
subtiliter ruguloso et sericeo, oculis divisis ; thorace supra 
inaequali, longitudinaliter elevato, subnitido, plagiatim 
sparse tomentoso ; elytris postice attenuatis, supra seria- 
tim sparse punctatis, fasciis duabus medianis approxi- 
matis, prima prope suturam interrupta, et apice late 
albo-testaceis ; pedibus rufis, tarsispallidioribus, femoribus 
sublinearibus, posticis apicem elytrorum attingentibus, 
breviter bidentatis ; antennis et tibiis posticis carinatis. 
Long. 44 lin. $ . 
The singular aberration in the form of the head amply 
distinguishes this species, as well as illustrates in a 
striking manner the instability of form of the most im- 
portant organs in a genus of Longicorns ; for the species, 
notwithstanding the division of the eyes into two on each 
