![Thumbnail: [Volume 88, 1960-61 page 152]](/journals/rsnz/images/rsnz_88/thumbnails/rsnz_88_01_0177_0152_ac_02.gif)
Pupation
In the previous account no pupae suitable for examination could be described. Two pupae were seen in March. The first, a male, was discovered at Arapuni, amidst a group of glow-worms, and a photograph of it is given in Pl. 9, Fig. 11, and a sketch in Text-fig. 2, Fig. 6 It was glowing as brightly as the glow-worms nearby, and it doused its light at the same time as did the neighbouring glow-worms when the flash-light was turned on the area. This pupa was only 9 mm in length, and was not sticky. It was suspended by a dry stiff thread 6 mm in length, which forked unevenly where it became attached to the bank. The pupa was detached from its position with a grass stem wetted at the end. Before it was touched, however, its reactions were observed for some time. It occasionally doused completely for as long as 15 minutes, and often glowed faintly. While it appeared to sense the presence of the observer, its behaviour was not quite the same as that of the glow-worms, for these soon lighted up again when the flashlight was put out, whereas the behaviour of the pupa was unpredictable. On arrival home, the pupa was examined with dissecting spectacles, and owing to accidental touching, the suspensory thread parted from the thorax as depicted in Text-Fig. 2, Fig. 6. The region of parting (mainly meso-thoracic) was clear of pigment, and of a dome-like nature. The pupa itself was not injured, and was placed on a leaf in a tin box. When this was opened in the morning, the pupa glowed brightly for about half a minute. It turned on the light certainly within three seconds, the light becoming gradually visible like the hot wire on an electric radiator just switched on. It was concluded that the pupa was aware of the flashlight turned on it, and that it was able to light up more quickly than had previously been expected. The pupa was able to move its abdomen slightly but not so actively as the pupae of some other holometabolous insects This pupa was fixed in Carnoy for sectioning.
The second pupa observed, a female, had undergone pupation during captivity. It metamorphosed from a large larva taken in the Botanical Gardens at Wellington during late January, and immediately adopted as suitable the arrangement of rotten boughs shown in Pls. 8, 9 and 10, Figs. 8–13. The larva (Pl. 8, Fig. 9) was fed on small house flies, whose wings were snipped off, and their head slightly squeezed so as to stun but not to kill them. The boughs were enclosed by an inverted chemical beaker 7in in diameter resting on wet earth. This larva, then 25 mm in length, was fed for more than six weeks, and it was therefore at first assumed that
![Thumbnail: [Volume 88, 1960-61 page 153]](/journals/rsnz/images/rsnz_88/thumbnails/rsnz_88_01_0178_0153_ac_02.gif)
it was not going to metamorphose during summer; but on the night of March 9, it was seen to be working away at the vertical lines of its snare. No special significance was attached to this, but on the morning of March 10, it was found suspended as in Pl. 10, Fig. 12, all vertical lines around it having been cleared away. The clearance was 20 mm on each side. Next morning it had pupated as in Pl. 10, Fig. 13.
Text-fig. 2.—Fig. 4—Newly suspended larva before pupation. Same specimen as in Pl. 5, Fig. 12. Fig. 5—Pupa 24 hours later, as in Pl. 5, Fig. 13. Fig. 5A—Three bottom droplets in vertical snare line, showing inclusions in mucus. Fig. 6—Pupa, as in Pl. 4, Fig. 11. Fig. 7— Thorax and suspensory region of newly metamorphosed pupa.
![Thumbnail: [Volume 88, 1960-61 page 154]](/journals/rsnz/images/rsnz_88/thumbnails/rsnz_88_01_0179_0154_ac_02.gif)
This pupa, a female, was ½ mm in length, and the suspensory thread was 10 mm before it forked. At this time the silken support was distinctly yellow. This pupa was fixed in Carnoy on March 13 during late morning. It will be noted that the larva was shrunken in length after pupation.
An attempt was made to examine closely the suspensory thread. By removing a microscope tube from its base, and holding this by hand, the appearance shown in Text-fig. 2, Fig. 4 was noted. There seemed to be a triangle of threads, one to the dorsum of the thorax, and two passing to the mouth region. A flat membrance appeared to stretch to each front line, from the thread attached to the dorsum of the thorax. Next morning the space between the threads appeared to be filled out with fluid as in Text-fig. 2, Fig. 7. Owing to the rarity of the specimen, it was not possible to risk touching it, but it did seem that mucus or liquid silk was passed upwards just before pupation, and when the larval skin split, this fluid presumably touched the emerging pupae skin and anchored it as the larval skin was discarded. In Text-Fig. 2, Fig. 5, the larval skin has been sloughed down, the head capsule at (LH) and the remains of the body cuticle at (AE). The pupa then three days old, was fixed in Carnoy, the legs (L) and developing wings (W) becoming loosened from the body. This pupa has been drawn from the dorsal surface and may be compared with the obviously more mature pupa got at Arapuni (Text-fig. 2, Fig. 6).
It is interesting that this larva from the Wellington. Botanical Gardens, which appears in the scries of drawings and photographs, Text-fig. 2, Figs. 4 and 5, and Pls. 3, 4 and 5, Figs. 8–13, never showed its light after it had adopted the site for its snare shown in the figures. The reason for this is unknown—but it might have been injured during capture. Nevertheless it led an active life during the weeks it was observed, and successfully pupated.
It could not be claimed that a satisfactory explanation of the fixation and origin of the suspensory line has been given. This will need close observance of more pupating larvae, and perhaps more satisfactorily, the killing of metamorphosing larvae at different stages so that the attachment of the line to the pupa can be examined properly under high powers of the microscope. But it is now clear that the suspensory cord is not a part of the thorax, that it is specially secreted, and that it is not the horizontal runway; the colour of the cord was yellowish after three days, and it becomes brown in the maturer pupa. If the cord is silk, as we believe, it appears that the silk must be mixed with some substance which goes yellowish brown on exposure to the air. This material might come from the mucus glands, but as has previously been reported, the mucus droplets of the larval phase are colourless. In older pupae and pupal exuviae, the main part of the suspensory cord is light chitin-brown in colour.
It should be mentioned that only one pupa was found in the field after six months searching at frequent intervals from late September to early March.