O SOLITARIUS. _C._ niger; abdomine petiolato; scapo flagellique
articulo ultimo, collari, tuberculis, postscutelli maculis duabus
flavis; pedibus petioloque basi ferrugineis.

_Female._ Length 5 lines. Black and opake; the head large, quadrate, and
wider than the thorax; the ocelli in a curve on the vertex; the clypeus
covered with silvery pubescence, carinated in the middle, and slightly
produced; the scape and basal joint of the flagellum pale yellow.
Thorax: an interrupted line on the collar, the tubercles, a spot beneath
the wings, and two minute ones on the postscutellum yellow; the disk of
the thorax longitudinally delicately rugose; the metathorax oliquely
striated, with an enclosed space at its base, and having a central
longitudinal channel, the side covered with thin silvery pubescence; the
wings hyaline and iridescent, the nervures fuscous; the legs
ferruginous, variegated with yellow. Abdomen: the basal petiolated
segment ferruginous, with its apical half black above; the apical
segment with an angular shape at its base, which is smooth and shining,
with its lateral margins carinate, the extreme apex ferruginous; beneath
smooth and shining, with the apical margins rufo-piceous.

_Hab._ Aru.

This species would, according to the views of some Hymenopterists,
belong to the genus _Rhopalum_ of Kirby.

Group SOLITARY WASPS.

Fam. EUMENIDAE, _Westw._

Gen. EUMENES, _Latr._

1. Eumenes arcuata, _Fabr. Syst. Piez._ 287. 11.

_Hab._ Key Island; coast of New Guinea (Triton Bay); Australia.

Gen. PACHYMENES, _Sauss._

1. PACHYMENES VIRIDIS. _P._ laete viridis; facie pube argentato-alba
tecta; alis hyalinis.

_Female._ Length 8 lines. Bright green; the head, thorax, and basal
segment of the abdomen rugose, the rest of the abdomen finely and very
closely punctured; the clypeus thinly covered with a fine silvery-white
pubescence, its apex produced and truncate. Thorax: the metathorax
rounded behind, a deep longitudinal impressed line in the middle, and
with fine silvery down at the sides and behind; the wings subhyaline,
with a fuscous stain along the anterior margin of the superior pair; the
legs rufo-piceous; the coxae, femora, and tibiae more or less tinged with
green.

_Hab._ Aru.

Gen. RHYNCHIUM, _Spin._

1. Rhynchium mirabile, _Sauss. Mon. Guepes Sol._ 106. 6, t. 14. f. 5
[Symbol: female].

_Hab._ Aru; Tasmania.

The _Male_ of this fine species closely resembles the female; it is
black, wit