50 Mr. H. W. Bates on the Longicorn Coleoptera 
catis, angulis externis vix dentatis: antennis nigris, infra parce 
setosis, articulo quarto basi pallido. Long. 42 lin. 
Head tawny ochraceous, vertex with two oblique flexuous 
dusky lines. Antennz black, two basal joints dingy ochraceous, 
fourth with the basal third of its length pale testaceous; they 
are setose, but the basal joint beneath is free from sete. Tho- 
rax on the sides tawny ochraceous, the middle blackish, with 
two oblique S-shaped streaks converging in front on the fore 
part of the disk ; the dorsal line is also dotted with ochraceous. 
Elytra strongly narrowed towards the tip, which is not spined, 
but obliquely truncated, with the sutural angle rounded off and 
the external one simply acute; the surface is furnished with 
rows of setiferous punctures; there is no posterior carina, and 
the colour is shining brown-black, with a sprinkling of tawny 
specks, some of which collect to form two indistinct narrow 
fascie, one near the middle, the other near the apex. Body be- 
neath dusky, with dingy ashy pile; margins of ventral segments 
whitish. Legs blackish ; claw-joints of the tarsi testaceous. The 
apical dorsal plate has shortish and rather blunt teeth. 
Valley of the Irura, Santarem ; on dead boughs. 
Genus OxaTHREs, nov. gen. 
Body elliptical, moderately convex, setose. Antenne fur- 
nished with numerous sete. Thorax as in Prodatius, its outline 
widening from the front to the tips of the lateral spines, which 
are small, conical, and placed behind the middle. Abdomen in 
the male with the apical dorsal plate notched or entire; ventral 
plate truncated and terminating in two stout teeth, like the 
dorsal plate of Probatius. In the female the apical abdominal 
segment is prolonged as a conical or short tubular sheath to the 
ovipositor, the dorsal plate tapering into a very sharp point, and 
in some species acutely carinated on its upper surface; the 
ventral plate is simply truncated in the female. Legs moderately 
short and stout; thighs abruptly clavate; tarsi short, even in 
the hind Jegs, much shorter than the tibiz, but the first joint 
slender and longer than the two following taken together. 
This genus, although closely allied to Probatius, is distin- 
guished at once by the bidentation of the apex of the abdomen 
existing on the ventral instead of the dorsal plate; but this 
is seen in the males only, the females differmg from the same 
sex in Probatius still more widely—namely, by having an ex- 
serted ovipositor and a prolonged pointed dorsal plate, instead of 
a bidentated one. 
1. Oxathres navicula, n. sp. 
O, ellipticus, rufescenti-fuscus vel obscure fuscus: thorace dorso 
