The New Zealand Railways Magazine, Volume 5, Issue 2 (June 2, 1930)
Life Stories from Nature
The science and study of insects, known as “entomology,” has come into great prominence of recent years. It is an extremely fascinating and aborbing study; the wonders are inexhaustible, rather do they appear to multiply and increase the further they are delved into. New Zealand offers a rich field for investigation and research to the young entomologist, who should bear in mind that many of the world's greatest enterprises have resulted from small beginnings. Should these “Life Stories” prove productive, as it is hoped they may, then their publication will indeed be amply rewarded.
There are very many forms of insect life that are most injurious to the physical and economic conditions of man; these, if permitted to increase without restraint, would cause absolute world disaster. Nature, who is the greatest of economists, has evolved an antidote against such a catastrophe by creating other insects, known technically as “parasites,” to destroy and keep in check those that are injurious; and, man, by closely studying her methods, has been able to utilize them to his own advantage.
Life Story of the Glow-worm Bolilophila Luminosa
Many of us have frequently observed those strange elfin gleams of phospherescent light so common in our New Zealand bush on dark nights, more especially in the damper places. These gleams emanate from the “torches” of one of our most interesting insects, the “glowworm” as it is commonly known; the splendid illuminator of the magnificent Waitomo Caves. The name “glow-worm” is rather erroneous and misleading, even though in the second stage of the insect's life it is a caterpillar, or “worm,” for, in its matured and final stage, it is a beautiful and delicate gauze winged fly.
This wonderful torch-bearer of Nature, throughout its three distinct forms in life, is a first cousin to the better known and more frequently seen, pretty and harmless Daddy Long Legs; it is also a first cousin of the still better known—and felt!—sandfly that bites so persistently and so painfully.
The “Glow-worm” is hatched from a tiny egg deposited by the mother fly in the crevices and cavities that abound in the damp soil of river banks, shafts, and tunnels of mines, caves, and other similar places. Immediately the caterpillar emerges from the egg it gets to work and spins its web across the recess in which it was hatched, and there it hangs through the caterpillar and chrysalid stages with “torch” gleaming brightly. It is of a brownish colour and about one inch in length when fully grown. The “torch,” which is at the extreme tail end, can be turned “on” or “off” at the insect's will, and is easily visible to the naked eye. The brightest luminancy is attained when the caterpillar is about to enter the chrysalid stage.
Strangely enough the “torch” seems susceptible to climatic conditions; it is invariably turned “off” on very cold nights and if subjected to any strong light. On the other hand the intensity of radiance is increased on dark, wet nights, especially with a gentle northwesterly wind in evidence.
The web is intricate in design, and formed from a sticky fluid exuded at the mouth, not, as in spiders, from spinarets at the lower end of the body. It consists of a “main thread” stretched across the mouth of the “home cavity” and held in place by smaller threads, crossing to the right and left, firmly attached to the sides and base of the recess in which it lives. From the main thread again, a number of smaller threads hang loosely and downwards that are always covered in small globules of moisture. If the caterpillar, which is very timid, is disturbed, the “light” is immediately turned “off,” and it retreats swiftly along the “main thread” to the farthest end of the recess, and vanishes within the darkness.
The chrysalid is a unique looking brownish object, about half-an-inch in length. It is firmly attached to a central web strand by a brownish coloured extension from the thorax, or chest portion. The eyes of the insect show plainly through the membrane of the chrysalid, and give it a peculiar “golliwog” appearance. The “torch,” which is still under control, is weak, and may not be turned “on” for days at a time. This dimness may be attributed to the organ of light being invisible and contained in the chrysalid case, consequently the rays become partially smothered in penetrating it.
The matured insect has a brownish body about half-an-inch in length, brownish gauze wings with a spread of half-an-inch. There are six long slender legs much like those of its cousin. The “torch,” which is placed in a posterior segment of the body, is only half as luminous as in the fully grown caterpillar.page break
Constructing Freight Wagons on the New Zealand Railways
(Photos, courtesy “Christchurch Press.”)
Building fifty “M” freight wagons at the Department's workshops, Addington, South Island. The wagons were constructed in a remarkably short space of time, the time interval between the taking of these two pictures being approximately eleven hours.