Introduction

In his last published work (1950), the distinguished entomologist, G. V. Hudson, stated, “the investigation of the habits and life-history of the New Zealand glow-worm has proved by far the most difficult problem I have had to face during the many years I have been privileged to work at the Entomology of New Zealand”. Nocturnal visits to caves and holes in banks where Bolitophila luminosa lives, do not provide the opportunity for quiet observation necessary for accuracy: the cave roof is often dripping with water, and the banks slippery. In 1888, the glow-worms in the Wellington Botanical Gardens were only obtained by Hudson and Norris by walking up the bed of a stream in the big ravine there. These glow-worms must have increased greatly, because they may now be seen along many paths above the ravine mentioned by Hudson, but are usually out of reach.

Hudson, whose great ability for breeding insects was well known, used a glass tank, the bottom of which was filled with a layer of damp gravel, in which a “cave” of suitable stones was built. He appears to have found that the glow-worms sometimes wandered and ate their weaker brethren or, worse, ate the precious pupae from which the unknown adults were expected to emerge. When, indeed, Hudson did breed an adult, in 1888, he sent drawings to the two specialists in the Mycetophilidae, Osten-Sacken (at Heidelberg), and Skuse (at Sydney), and both refused to believe that it was the adult of the glow-worm larva of which Hudson had already sent them specimens!

In 1956 fixed larvae were sent to the writer's laboratory at Dublin. Fairly complete serial sections, and whole mounts were made, and these were used by the writer and Gouri Ganguly for anatomical study. No live specimens had been examined, nor were the pupae or imagines available. It was not possible to dissect the fixed larvae properly. Enough cytological preparations were made to show that satisfactory study of the light organs would need electron microscopy. Recently three adult specimens of this insect were discovered at the Waitomo Caves, and parts of the male and female were sectioned in order to ascertain the condition of the luminescent organs, said to be present in the female by G. V. Hudson and A. Norris. At Waitomo and elsewhere, a search for pupae proved abortive, though

what appeared to be pupae hanging from the roof of the cave were seen. These could not be reached. A somewhat similar cave at Waipu, North Auckland, was visited, and two complete pupa cases and several incomplete parts were found. In addition, the region at Arapuni, near Putaruru, where the original specimens for study at Dublin were collected, was visited several times, and some experiments were carried out on the larvae.

Some of the gaps in our knowledge of these peculiar insects were thus filled, but more work is necessary.