I've had to really brighten this photo and enlarge it so you can see these things. They are holding gatherings on my crocosmia leaves.
They look and behave like tiny tiny very fast moving caterpillars, are black and the only thing I can compare them in size to are chocolate vermicelli that people sprinkle on cake icing. Each one is about 10mm in size. In this photo they are grouped on the leaf in about a one inch square.
Anyone know what they are? I brushed them off with my hand - but should more groups of them appear - are they considered foe or ought they to be left to go forth and prosper?