RUS MODESTUS. _O._ niger; abdominis segmentis duobus basalibus
flavo fasciatis; tibiis tarsisque femigineis; alis hyalinis; abdominis
segmento primo basi transversim bicarinato.

_Female._ Length 4 lines. Black; head and thorax coarsely punctured; the
vertex swollen; the scape of the antennae, a spot between them, and the
clypeus yellow; the latter with a transverse black spot in the middle,
deeply notched in front, and having a carina on each side, in a line
with the angle or tooth of the emargination; the flagellum ferruginous
towards the apex beneath; wings hyaline, with a fuscous cloud in the
marginal cell; the tibiae and tarsi ferruginous. Abdomen: the base
truncate, with an oblique space above the truncation, the margin of both
defined by an elevated ridge or carina; a narrow fascia on the apical
margin of the basal segment, and a broader one on the second; the latter
continued beneath the abdomen.

_Hab._ Aru.

This species is undoubtedly allied to _O. Sichellii_ of Saussure; but,
beside differing in the colour of its legs, and of the bands of the
abdomen, it wants the strong tubercle at the base of the second segment
of the latter.

Gen. ALASTOR, _St.-Farg._

1. ALASTOR UNIFASCIATUS. _A._ niger; macula inter antennas, abdominisque
margine apicali et segmento secundo flavis; alis fuscis.

_Female._ Length 6-1/2 lines. Black; the head and thorax strongly
punctured; the face, sides of the clypeus, cheeks, and base of the
mandibles with a fine silky silvery-white pubescence; the clypeus
convex, its anterior margin emarginate; from each angle of the
emargination a shining carina runs more than halfway up the clypeus; a
minute spot between the antennae, and two on the anterior margin of the
prothorax, yellow; the wings fuscous, palest at their posterior
margins. Abdomen finely and closely punctured; the third segment
strongly so; a broad yellow fascia on the apical margin of the second
segment.

_Hab._ Aru.

2. ALASTOR APICATUS. _A._ niger; abdominis segmentis primo et secundo
aurantiaco-rubris; alis fuscis.

_Male._ Length 5-1/2 lines. Black; the head and thorax strongly
punctured; a spot between the antennae, the scape in front, and the
clypeus yellow; the latter with a large black spot at its base,
anteriorly deeply emarginate; wings fuscous; the tegulae with a
rufo-testaceous spot at their outer margins; the tarsi and articulations
of the legs ferruginous. Abdomen bright orange-red, with the third and