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Show 1 9 0 2 . ] SPIDERS FROM BORNEO AND SINGAPORE. 263 wings resplendent with metallic blue sheen, occurs commonly on the mountains near Kuching. On Mt. Santubong a fly was recently captured affording a close resemblance to the wasp. The body and legs are exactly of the same shade of colour as are those of the wasp ; the wings, though somewhat browner, are more opaque and possess a blue metallic sheen sufficiently deceptive. Their size is large (larger than the fore wing alone of the wasp), and it is interesting to note the same downward curve of the submedian vein as was found in Hyperechia feva, suggesting the line of junction between a fore and a hind wing. The antenna? are fairly long, though far shorter than those of the wasp. I have not seen this species in the living state, but even as a cabinet specimen it is a remarkable case of deceptive resemblance (compare figs. 11 & 12, Plate XXII.). Specimens of this fly from the Philippines and Tenasserim are in the British Museum collection of Diptera. v. Mimic. Physocephalci sp. (Fam. Conopidse.) Model. Isahnogaster micans (Sauss.). This example has been selected at hazard from-a, large number of similar thin-waisted flies, chiefly Syrphidse and Conopidse, as typical of the method by which the similarly built Eumenidse and Vespidae are mimicked. The first abdominal segment is much attenuated and drawn out, those following are thickened; the transparent wings are shaded with fuscous on their anterior borders, in accordance with a similar arrangement in the wasp ; the head is the only part which exhibits any of the yellow colouring of the model. vi. Mimic. Gen. et sp. ? (Fam. Stratiomyidse, subfam. Eaphio-cerince.) Plate X X II. fig. 6. Model. Mesostenus sp. nearpictus (Smith). Plate X X II. fig. 5. Both species were taken on Mt. Penrissen on the same day, and the similarity of their external appearance was equalled by the similarity of their method of flight and action when at rest. The Ichneumon-fly was common enough, and was frequently seen to hover over a plant for a few minutes, then suddenly drop clown and pitch on to a leaf, over which it would walk, moving its white-banded antennae up and down with a quick flickering movement. The fly, of which only one specimen was caught, behaved in exactly the same manner; it would hover, then suddenly settle and walk over a leaf on its mid and hind pairs of legs, waving rapidly up and down its long front legs, the tibiae of which being black and the tarsi white, most closely resembled the antennae of the Ichneumon-fly. The femora were kept more or less pressed against the ventral surface of the head, so that the sham antennae seemed actually to arise from the correct position. This method of bringing about a resemblance to long antennse is |