_Female._ Length 6-1/2 lines. Black; the abdomen with tints of blue violet; the thorax slightly prismatic; the labrum, clypeus, an angular scape above, an abbreviated line on the inner orbits of the eyes, the scape in front, and the antennae beneath, yellow; the cheeks with a silvery reflexion. The thorax beneath, and the metathorax, with a shining white silvery pile; the anterior and intermediate femora and tibiae beneath yellow; the tarsi pale ferruginous, and more or less fuscous above; wings subhyaline, the nervures fuscous; a spot on the lateral posterior angles of the metathorax, two ovate spots on the scutellum, and a line on the postscutellum yellow. Abdomen: the basal segment with a broadly interrupted fascia a little before its apical margin; the second and fourth segments with a narrow yellow fascia at their apical margins, which is widened laterally; beneath, the second and third segments with a yellow spot on each side. The _Male_ differs from the female in having a large quadrate black spot on the clypeus, and a spot at the base of the labrum; there is also a narrow yellow line on the posterior margin of the prothorax; and the third segment of the abdomen has a yellow fascia: it is also rather smaller. _Hab._ Aru. This insect very closely resembles _Larra prismatica_, from Borneo, Malacca, and Celebes, of which it may be a variety. Gen. BEMBEX, _Fabr._ 1. Bembex melancholieca, _Smith, Cat. Hym._ pt. iv. p. 328; _Proc. Linn. Soc._ ii. p. 105. _Hab._ Aru; Sumatra; Borneo. Many of the specimens from Aru are less highly coloured than those of Sumatra or Borneo: the yellow markings on the abdomen are frequently much obliterated in the females; others are as highly coloured as any examples I have seen. Gen. PISON, _Spin._ 1. PISON NITIDUS. _P._ nitidus, niger, distincte punctatus; alis subhyalinis, venis fuscis; segmentis abdominalibus apice depressis. _Female._ Length 5 lines. Black and shining; the head and thorax strongly punctured; the face beneath, the antennae, the clypeus, cheeks, and the sides of the segments of the abdomen covered with a silvery down; the palpi pale testaceous; the mandibles obscurely ferruginous at their apex. The metathorax transversely striated behind, with a central longitudinal impressed line above, which is transversely striated, and terminates in a deep fovea just beyond the verge of the posterior inclined truncation; the wings subhyaline; the nervures dark fuscous; the first recurrent nervure received at the apex of the first submarginal cell, and the second at the base of the third submarginal. Abdomen shining, and more delicately punctured than the thorax; the margins of the segments deeply depressed. _Hab._ Aru, Key Island. Gen. GORYTES, _Latr._ 1. GORYTES CONSTRICTUS. _G._ niger; clypei lateribus flavis; collari, tuberculis postscutelloque flavis; segmentorum abdominis marginibus apicalibus flavis constrictis, pedibusque flavo variegatis.