NATURALISTS' FIELD CLUB

Evening Star, Issue 19352, 11 September 1926, Page 21

NATURALISTS' FIELD CLUB

The fortnightly outing of tho Dunedin Naturalists’ Field Club was spent in examining the native plants in the vicinity of Carey’s Bay and Deborah Bay, about 123 different species, including ferns, being noted. Among the less common plants growing on tho hillside wore dianolla—a grass-liko plant of the lily family—and scurvy-cress (Lepidium oleracoum). On the outskirts of the bush on tho hillsides thex - e was an abundance of manuka and other scrub, Coprosma aorolata being conspicuous, while Kaikomaka and tho milk tree (Paratrophis hoterophylla) were also represented. A number of ccprosmas wore in flower. In the bush there was a good variety of ferns, including three tree ferns Hematclia Smithu, Dicksonia squarrosa, and the silver tree fern (Cyathca doalbata). Asplonium Richardi, A. bulbiferum and intermediate forms were noted, as well as two or throe of our more beautiful ferns, Leptolepia novae-zealandia, Dryoptera hispida, and D. glabella).

NEW ZEALAND SPIDERS

At the indoor meeting, Mr W, Martin B.Sc., gave an interesting talk on Now Zealand spiders. Though some people have an innate horror of these liarmless little creatures, Mr Martin’s lecture proved them to be wonderfully interesting and ingenious. New Zealand possesses about 300 species already described, though there are many more which have not yet been identified. Mr Martin touched briefly upon tho anatomy of spiders, and outlined the main distinctions between them and insects. Spiders do not pass through a metamorphosis; they are born spiders from the egg and grow to maturity by a series of moults. They possess the power of renewing the limbs, and n they lose a leg, it is replaced at the next moult. They are air breathing creatures, have a nervous system, ami brains. They have six or eight simple eyes, the arrangement of which is constant in genus,_ and is therefore made much use of in the identification of species. Individual species are also distinguishable by tlieir_ habits. Air Alartin’s lecture dealt chiefly with the habits of wolf spiders, trapdoor spiders, water spiders, orb weavers, line weavers, leaping spiders, lube net spiders, crab spiders, crab spiders, and Katipo spiders. There are eiglu species of spiders commonly called trapdoor, but not ail build trapdoors. The ones which make trapdoors usually build their "homes in a flat or sloping surface near a tuft of grass or mound where tho roots tend to keep the soil dry. They make a cylindrical tube with tho cover portion slightly larger than tho rest, and when pursued they take shelter and hang on to the lid and burrow with their legs. The outside of the lid is always made to match its surroundings by the buildei placing upon it pieces of grass, tussock, etc., according to the vegetation round about it. Several of the species, which live in tube-like burrows, do not built lids, but have an ingenious method ol catching their prey. Tho month of the hole Is left open, presumably with the intention of attracting the curiosity ol insects, which crawl down the hole, while tho spider lies in wait in a side tube and attacks its victim in the rea" .

Of tho water spiders five distinct species live in the water around the coast. They are air breathers, and come to the surface for a supply ol air, which they take down on the hairs of the body. One species takes air down in a bolt-like structure, and lives under water for some considerable time before returning for a fresh supply. They feed on small forms ot marine life. Besides those, there arc others which live in fresh water, and there are at least two species in the Leith. Two others occur in Central Otago, and one is common in the waters of Lake To Anau and Manapouri. These spiders are unable to dive, and in order to get into tho water they have to descend down a stick or stem. Line weavers are extremely numerous and very considerable. Of the leaping spiders, there is one species here which has a flat body and lives in paling fences. When hunting its prey it moves with extreme stealth, advances by stages, then pounces on tho back of its victim. It also takes precautions _ for its own safety by anchoring itself with a strong wed) before leaping. Tho habits of many other spiders wore dealt with in a very interesting manner, and at the conclusion of his address Mr Alartin was accorded a hearty vote of thanks.