Paraleptamphopus caeruleus (G. M. Thomson).

Paraleptamphopus caeruleus Chilton, 1909B, p. 54 (with synonyms).

This species is now known to be widely spread over the southern portions of Otago and Southland, It has been recorded from Swampy Hill (near Dunedin), from the Old Man Range, from the neighbourhood of Invercargill, from Ruapuke Island, and I have recently collected it in abundance from several localities at Drummond and Otautau in Southland. In these places it lives in ditches and small streams on the various weeds that grow in the water, in much the same way as the ordinary fresh-water Paracalliope fluviatilis does, though this species was not found by me in the same ditches. With P. caeruleus there was, however, the other species, P. subterraneus, but it was usually found a little deeper down, either on the surface of the mud or actually in the mud. P. caeruleus is slightly smaller than P. subterraneus, and can readily be distinguished by its dark-blue colour. Most of the specimens are so darkly coloured that they appear black, but some are paler, especially on the appendages.

The differences in structure from some of the forms of P. subterraneus are few and unimportant. The one that seems most constant is in the telson,