M. M. Brewster, A. A. Brewster & N. Crouch, Life stories of Australian Insect, Sydney, Dymocks Book Arcade, 1946, p. 71-72
One of the common caddis worms of the Family Sericostomatidae builds a little cylindrical case which is broader at one end. ( Plate 13, Fig. 9.) On examining with a lens, the sand grains, which were translucent, were seen to be beautifully cemented ; the average grains were uniform in size, with smaller ones fitting into smaller spaces between the larger grains. On examining one of these cases we found that the broader end seemed to be completely closed in by a « door » made of three large central grains with an outer circular row of smaller ones (Plate 13, Fig. 10.) The narrower end was darker in colour and was partly closed with a particle of plant tissue. Within this brittle case was a perfect pupe, showing wing pads and long antennae. (Plate 13, Fig. 12.) One of the comon genera found about Sydney in pools is Notonatolica ; another Helicopsyche, which makes a snail shell tube into which it retires on resting, and this species is only found in running streams. Another is Hydropsyche, which lives in a home made of a few pieces of gravel, etc., grouped together on rocks.
Observations on the Larvae of Caddis-fles. (Notonatolica)
We obtained some larvae of caddis-flies from a stream in a gully at Thornleigh, in May. We brought them home and also some sand and water weed (Callitriche) and placed them in a glass bowl, and spent some very enjoyable hours watching them. At night we put in the bowl out in the garden near some cannas, and each morning brought it in and place dit in the sunshine. The larvaa, which were resting when first brought in, soon became lively as the warm unshine played on the bowl, and set to work in a very business-like way to get breakfast.
The cases were about half an inch to one inch in length (according to the age of the larva). Each case (Plate 13, Fig. 7) was narrower at one end, for as the larva develops it increases the size of the case. It was made of little scraps of stems, leaves, etc., cemented with interwoven threads to form a complete bag-like canal, for, at the posterior end was a clear piece of woven material with a little circular hole in the centre ; there were only a few « scraps » sewn in on the edge. (Plate 13, Fig. 7a) This would allow of circulation of water through the case and for exist of excreta. One larva had chosen a piece of a hollow rectangular stem about ¾ inch long, and had covered the ends with a membrane-like material, with a few pieces of stem and other material woven in, and at the posterior end was the little circular hole before mentioned.