Black and Green Marabou, or with a light olive green body, a Kemsley's Green Marabou. Either way, it is a top New Zealand trout lure pattern for both brown and rainbow trout. The bottom picture shows the same lure once it is wet.
Black and Green Marabou Fly – Trout Streamer Fly – Gary Kemsley

Black and Green Marabou Marabou style flies are now sold in just about every colour.

Brown Trout – Salmo trutta – Identification and Introduction Guide

Brown Trout Salmo trutta – Colouration, Identification, and Introduction into New Zealand The brown trout.