THE NATURALIST.

Otago Witness, Issue 2372, 17 August 1899, Page 54

THE NATURALIST.

Sand Flies. By Richard Henry.

Visitors are generally astonished at the numbers of sandflies in lonely places on the West Coast and wonder at their .ability to bore holes and suck blood as if they had been brought up to it though their fearlessness almost proves that they never had a bite at an animal before. They are so indifferent about being killed that we are almost forced to believe that they know nothing of resentment from their victims, and that their intelligence was only designed for biting arid sucking the juices of plants. What a pity they ever learned the superior quality of the warmer juices of animals! We only consider them a nuisance, and often ask what they were made for, forgetting that the same question might be asked about men ; but a few old identities may remember when sandflies were plentiful in Dunedin and when coughs, colds, and doctors were correspondingly scarce, but no one will credit this delightful state of affah's to the sandflies. However, I have been five years in DuSky Sound, Avith plenty of sandflies, and only caught, one cold in all that time, while I usually catch a fresh one every, month in Dunedin, with no sandflies and a climate apparently perfect. There are two theories about the utility, of mosquitoes. The first is that they innoculate new arrivals with a mild fever to save them from a more virulent form, on the lines of our vaccination, and in this light are benevolent. The colds so rife in Dunedin may be called " cold country fevers." The other theoiy is : That the mosquito sticks its beak into some fevered pkin, and then carries the contagion to some new arrival, and deliberatly bores a hole for its deposition, which may still be benevolent, because that new arrival may not be constituted to live a happy life in the mosquito country, so that a quick despatch may be more human than years of misery. Perhaps the niosquitoes don't consider money-making to be the white**man's principal business there, and give him a gentle reminder first and then a peremptory order to make room for more suitable people. Some might suppose that if the mosquito was benevolently inclined, it would dip its beak in some antiseptic before using it on another patient as the doctors do with their instruments. For all we know to the contrary, that is just what the sandfly may do, for it may be a bit of an herbalist, and know as much about good medicine as it seems to know about good food. According to the universal idea, Dusky Sound should be an ideal place for rheumatism, but if it was not for wearing oilskins I think there would be no rheumatism there, though the land is all covered with bush and moss that never dries, for the average rainfall is about a foot a month, with wind in proportion.

With one day's acquaintance it is easy for anyone to prove that it is not the smell of blood that is so attractive to those flies, but; simply the radiation of heat, and as I do not suppose that they can smell heat I get an idea of their fine sense of feeling — finer than any thermometer. A potato after breakfast will attract them just as Avell as a warm hand or face, and they know well- when anything is too hot for them, but when a billy of watei cools to the right temperature they will crowd round it eagerly, and I have no doubt may blunfc their knives and lances trying to bore holes in the tin. I habitually make use of this keen sense of feeling to trap them in scores of thousands by painting an iron cylinder with fat, keeping a fire tin inside and adjusting the heat by the supply of air. When this trap is going for an hour or so. I can go round the clearing or out fishing with comfort, knowing that the heat has attracted nearly all the flies within a radius of several hundred yards, and I believe that they could feel the heat of my hand at a distance of fully a hundred yards. What is almost as wonderful, no one seems to know where they lay their eggs, or in what form their young are developed. I have a splendid opportunity to find oiifc their secret; breeding place, but know nothing about it till the pale-coloured fly lights on my hand, proßablv only a few minutes after leaving its shell.

—An Irishman at the seaside was watching a steam dredger at work iir the harbour. " Are you coming home, Pat? " shouted a friend who was passing. " No, shure, until I have seen the last of these buckets. I have counted 14,000 of them, and they be still coming up. Begorra, I don't go away till I see the last one."