THE MOSQUITO'S HAUNTS.

New Zealand Herald, Volume LVIII, Issue 17662, 24 December 1920, Page 1 (Supplement)

THE MOSQUITO'S HAUNTS.

CULTIVATING A PEST. BY INVESTIGATOR. Few creatures display a more devoted attachment to mankind than the mosquito, or are less discriminating in the choosing of their hosts. But in spite of the intimacy of our acquaintance, our knowledge of them is, as it were, only skin-deep. With, in the next few months, the opportunities for entertaining thein will be renewed, a<s sunshine and showers quicken their social instincts, and those who are at all curious regarding these summer boarders should study their biographical record, recently, issued from tho Government Printing Office. There are limit® to hospitality, and the mosquito oversteps them. She is a chamber musician, but her enthusiasm is generally untimely, and when she pauses for refreshment, she makes her host serve as buffet as well as audience. There are males in the background, but it is the female that preys upon mankind, while the gentler sex of the species is content to dine upon vegetable juices. That much we may learn by personal investigation.; the Government Entomologist's report, describing an investigation of mosquito haunts and habits, from Auckland to the North Cape, reveals the reaspns ?rhy they are so commonly encountered,, and suggests means jjye should employ to dismiss their unwelcome company.

A New Species discovered. Mr. Miller's first purpose was to discover syhether the carriers of yellowfever and malaria have become established in New Zealand- His conclusions were negative; completely so in respect of the yellow-fever species ; and practically bo in respect of the malaria-carriers, though the evidence in regard to them was not conclusive. Conditions in the North Auckland peninsula, &re favourable for diseasecarrying mosquitoes, and as there are many malarial subjects residing in the country, especially since the return of soldiers from the tropical campaigns, there is additional reason for precautionary measures. ir'ivg species of cuijpines ? preyipuely recorded, are ip be> cojn r mpn; additipnaj ppeaes bf?B been identi; figd. the latter including tb© discovery pf " b. ppiqug species, botb sexes of syhicb snck blood; thi§ form will be placed in a nes: ggnug. jloubtigggi a n§s? §ub ; family Kill to bg pr£at§,d for its fgcggtion os?ing f# peculiar an£tpmjb§.l. structures of laryaj pppa an<|- adult." The new type fpppd along the northern coast-line ? brackish collects, and is fp ol *? tP Hgngau^u Bay, in the far North. It is "particularly vicious." Nurseries in Stagnant 'Water. Two species are of most frequent occurrence- One goes abroad by day and! is not very troublesome; it is alsp an urban cj'yeiler, being restricted, ahnost entirely, to Ancklan<| city. The other, which Mr. Miller very mpderatsly describes as being nocturnal and inflicting painful wonnds, ravages thg whole peninsula. The nomenclature Gulex Pervigilans strikes the ear ag singularly appropriate. Wherg they originated, and yherjj they acquired their depraved appetites, is not material- Their' continuation ' depends upon stagnant — anything from a spoonful "of opllegt-ed by a chscfrpigd tin, tg a plug'gish Cfggk? or an undrained purpose. The females hibernal© in moist cellars in Queen Street foiaiid. tj> accommodate the'jn — and waging with the spring, lay eggf Wggn |b§ nearest Bgitabl© ejtne?: fjugjy §r in masses; •Hb'e latter resemble ljttie "curved chips pi wood, like the payings of a lead : penril. floating on the' -ymtSr." The aquatic stages of egg, larva, and pupa, are completed within a. fortnight, the pupa releasing the fully-grown &4ult to perpetuate its kind. and to persecute our kind. $lethoss of Attack.

There are classic examples pf success in the jEshmination 'of mosquitoes from human communities. ' Wai uppn the adults is hopefes's';#£be only method' is to attack the |pgpi|g"'in its places, by preyenting or ""draining" stagnant >ya'ter, or by drpwnmg thp'''!ars»' and tb© pup ß ?, by "'piling?- tHp"surfac'e sp'tliat their 'breathing apparatus ff'nnot reach the air. JSlpwflowhig streams, particularly those choked Wit-df} fepgs and swamps; pf mountain streams';' bojes in the trunks of Forest trees; the water collected in the leaf bases of such plants as the banana-palm and the epiphytic astelias, the strange parasites that tuft the limbs and trunks of trees; these are the principal natural locations of the mosquito. Artificial means of propagation are provided by anything that will collect and retain water — old tins and bottles, choked roof-gutters, gully-traps, water tanks, and barrels. The report does not mention it, but when the bedroom jug contains a colony of re-markably-active "wrigglers." there is evidence that mosquitoes have discovered a careless housemaid. The natural breedingplaces are not easily controlled, but most of the artificial ones exist because of our carelcss and untidy habits. Breeding Places in the City. 'Xlr. Miller's field-work vrAs evidently thorough. He has catalogued most of the sources of mosquito invasion, and the list should stimulate a radical improvement. Within the greater part of Auckland city, artificial breeding-places alone exist. In the sluggish creek of Grafton gully, and in old water-filled tins, ".which abound hereabouts" — the beauty of this public property will not bear too close scrutiny— in the creeks of the Domain, and between Waterloo Quadrant and the harbour, swaa-rns of mosquitoes were found. Collections of old tins on Shelly Beach, a -pool of water in Nelson StTeet below a rubbish tip, Cox's Creek, Motion's Creek, Cabbage Tree Swamp, all disclosed the teeming life of mosquito haunts. The larger bodies of water, such as Lake St. John and Lake Pupuke, are free of the pest, owing to the activity of aquatic insect enemies. Similar conditions were found wherever the investigation proceeded; the rustv tins and stagnant catch-basins of the towns being replaced in the country districts by swamps and weed-choked streams. The progress of settlement is restricting the permanent natural .locations of the mosquito, but Mr. Miller considers that more rapid measures of control should bo taken. Protective Measures. The clearing of weeds from stream-beds is the obvious remedy in many cases. Wherever it is impossible to prevent water standing, oiljncr of the surface with kerosene or on a larpe scale with a mixture used in the Panama 7one is recommended. Tanks or wells for drinking-water ran be effectively treated with copper sulphate, without injury to its domestic use : the proportion advised being one part of sulphate to 5000 parts of water. The presence of mosquitoes is not merely a source of discomfort. So long as the species is allowed to breed freely, and even encouraged to do so by neglect and carelessness, i the risk reroa-'ns of disease-carrying forms j becomins; established. Further, the prei pence of the larvae has been shown to in--1 crease the bacteria! contents of water. [ The mosquito has abused our hospitality I beyond pardon. Her singing is an offence, i her feeding an outrage, and her existence | a defiance of sanitary knowledge. Tf we I allow her to remain, we. alone, are to i blame.