Norman Marsh, Trout Stream Insects of New Zealand, Auckland, Halcyon Books, 2004, p. 65.

The stomach of a one kilogram fish caught in a small limestone stream on opening day of 1975 contained no less than eight hundred and sixty-four cased caddis larvae, plus seventy mayflies, eighteen beetles and four creeper larva../..The former protect their soft bodies with tubes-purse or shell-like cases- and are covered with an amazing variety of material. Those of interest to the angler are the tube or horn cased caddis which produce a self herdening secretion and form a tapered ring case to which stick minute particles of sand, tiny pebbles, gravel, lignite, coal, leaf particles and any other material handy to its habitat. The curious fact is that particular species seek out material peculiar to themselves.