a drop of silk from its mouth onto the rock, thus forming a fine thread which acts as a brace. Then it repeats the process, moving forward into a droplet of silk and mucus. This process is repeated till the mucus and silk have passed down the whole length of the body and the nest is complete and hollow. It is approximately 2.5 times the length of the larva, or about 10 cm. for a fully grown larva (Plate 11, fig. 1). The nest is very plastic and enables the larva to glide rapidly backwards and forwards at will. When at rest the larva lies on its upper side, and even when moving about backwards and forwards it keeps its venter turned upwards.

From the nest a larva lets down up to 70 strings of sticky droplets. Depending on the size of the larva, the fishing-lines formed in this manner vary in length from under 1 cm to 50 cm. They are remarkable for their great tensile strength (Plate 3, fig. 2). Fishing-lines are formed in a peculiar manner. Each consists of a long thread of silk which bears at regular intervals a series of mucus droplets giving the appearance of a string of beads. Droplets vary in size according to the size of the larva, but average 1 mm in diameter and 1.5 mm in length. To form each droplet the larva thrusts its head forward three times, and then, with five short jerks, withdraws it into the thorax, when a drop of mucus and silk is ejected after much movement of the jaws. During this process, the anterior half of the larva's body hangs vertically from the nest. The larva is able to break through the nest at any point along its length to let down or haul up fishing-lines.

A nest can be built in as short a time as ten minutes. One larva in Waitomo Cave, after having its nest destroyed, was observed to crawl up the wall a few inches to another niche. Within twenty minutes it had built a new nest and let down two fishing-lines, each 3 cm in length.

Formation of fishing-lines is a continuous process in which the larva moves along the nest gradually increasing the length of each fishing-line. It does not complete the full length of one before commencing the next. These fishing-lines are very delicate and so close together that even the slightest air current may cause the sticky threads to become entangled so that the larva is constantly repairing its snare. In the bush and along stream banks glow-worm fishing-lines are usually only a few millimetres long (Plate 29, fig. 1). At Waitomo, their great length is probably made possible by calm conditions present in the cave (Plate 37, fig. 2).