ENTOMOLOGICAL FIELD-WORK

New Zealand Times, Volume LXXI, Issue 4082, 21 June 1900, Page 2

ENTOMOLOGICAL FIELD-WORK

ADDRESS BY MR G. V. HUDSON,

- At the meeting of the "Wellington: Society on Tuesday night, Mr-,G;V. xiudson, F. 8.5.. devoted his presidential address tp ■“General Remarkb'- on Entomological.. Field-work inNdwiZcaland.” Air Hudson thanked; the mepibers for the very great honour, they Had conferred on Tiim by electing him to .the position, .of presid.egt pfiAhe . society, and assured them -that” he would endeavour to perform the duties of the office to-the best of his ability. Entering upon. Jus subject, he said that in any country where the insect fauhaj was incompletely known, . it might be safely said that the first and most im-j portant step to-be taken by the nak t Lira list was the formation of good and! exhaustive r 'odllectiohs - - of ‘ specimens.! That was especially the,,case in New’, Zealand, ■ where theprogress' - of ■ settle-i ment and the tintroduction of domi-i nant forms of .life wore producing thol most rapid add far-reaching changes in] , the original • inhabitants/ both animal! and .vegetable.. He considered That forest] collecting was: at--present one of thej most important | branches of field-work] that the New . Zealand] entomologists] could takei up i . The best months fori forest collecting in the-lowlands of New] Zealaiid -(localities -not (exceeding ,15,00 feet above tfie sea levej)) were November, . Dpcember and January,. December being really the best of all. • He had found that forest 'ravines or river.-gal-* leys, were much ‘morel productive in- in-j sects than hill-bush fan removed from water. The. black-birch (or beech) forests] which were so common on high ranges, were comparatively poor in in-i sects, though ' they sometimes yielded species ’ riot, found , elsewhere. One very interesting feature connected with our forest-dwelling ■moths 'was "their extreme variability and their very wide geographical range, so far as New Zealand was concerned. He had much pleasure in exhibiting a number of specimens illustrating both these points; Each of the', species of. insect selected would be , sepja to ; vary ..very . much within the limits..of ,ithe, species, and all those represented had been taken at various localities from Wellington southwards as far as Invercargill and Stewart, Island. Unfortunately, but little collecting of Lepidopterar haid at present been done in the north, but Captain Broun had investigated the; boefcles of that'-r'egion" with indomitable energy, as his-volumes oD-published descriptions of. additional species abun/ dantly testified. Some experts in' the study of the Coleoptera considerdd,. Mr Hudson believed, that a very sub-stantial-reduction;, in. thef number" of species described -by-the learned-cap-tain would ultimately prove necessary but, be' that as it might,"the name of Broun would" "in future undoubtedly! be associated with a very-great number of species ,o‘f New Zealand beetles.! Continuing,’ "Mr Hudson • .said: : —“The; destruction, of .the-forests in the vicinity of Wellington is,, of course, a trite subject to every pne,.,qnd many members can no doubt remember far greater changes..iii-tliis_respect_tlian-I-oani - I may instance, however, as a probable result of this destruction, the striking decadence in the numbers of two coml morr insects ' which has taken place; within my experience of some eighteeii years j only. . i .During the sunimei’| of 1882-83,- which wals the first, season that I collected insects , at Karori, I remember that, at evening dusk the aiii was literally 'swairming i with specimens of Hydriomena ’delt'didala.,These were so abundant! .that .four or five specimens would 'fly out of a 'single bush and frequently two or three. specimen;: would he captured in the net at oncoj In fact the abundance of this .particu| lar", species, was ,mosb embarrassing t«J ilio collector,’ as it was liable to. bo mist taken, for mai}y;:rarer;;ithough;somewliaf similar;^species;; i. East summer..(lß99i 1900) 1 certainly, did not see; more, than a dozen / sphcinijCha,', of ‘ H. ' dcltoidata; and it . cannot - ,: mow bo caUedya, really abundant, species; 1 1 have.noticed. tho- insect steadily.deeliningin numbers during the, whole of my entomological/ experience in. the neighbourhood 'of ■ Wellington,! aud,-,l- am'-iiidirred do mttribiitts - itypart-t ly to 1 .the - increase ini/.'tlie number of sparrows; and'"partly ‘ to '’the .denudation of the a forests, for, although I have only found itffi'e'.larraiof.itliis insect feed ing ' oh : a“ species' of Plantago, I am inclined ,tQ-.think. that-it-also- probably feeds on some of our native ferns. The moth used to be most abundant amongst luxuriant patches of ferns in rather open spots in the forest, and it is still common in such localities, when' these as©'situated'far away from settle-1 ment. Another..species .that has declined equally- in , numbers, during the same period is- Somatochlora- smithiij Duing the past, three years I have been 1 specially, ..anxio.us; to ■ obtain;; many ex-! amples of this, and, in fact, of all our] native dragon-flies, and its comparative .rarity has consequently been somewhat; forcibly . brought under'my notice. In 1883,Tremember, this insect was abun-* dant over,, every, stream in Karori, and; at that' time I used i to frequently ob-! serve; the 'females depositing their eggs} in the; yvktef,' , t l h6 ..long;', abdomen being beatep, violently » on. the-.^rf ace -during the jirocessj . Now,- hdwevjer, it would be quite impossible to ' make any such observation. In .fact. 1 during the whole! of the past •■summer F saw only two 1 specimens. at . Karori. and these • seemed] to have come .from .;a. distance, as they? were, flying : very.-'high, in the air, ap-i parentljr migrating; The ’ larva of this insect jives l in- the/mnd “at the bottom! of stagnant "streams and ponds, and •may, 'perhaps,':"Have, been, destroyed by] the ever-increasing number of. trout,! otherwise, it i is,/difficult to; understand what ~ causes can have led to the great decrease . which, has taken place in the numbers; of’ • the iperfect ■ dragon-fly. In-i troduced insectivorous birds, through; feeding on the *'imago’, l may - again;.. be suggested, as, ,a , .cause-,of Vdecridence:! yet- "tlfi ‘'insect/ is "ah 1 , extremely' rapid flier, , jandr should bey able- to (avoid; cap 4 ture to ; ,a • great extent. However, the facfcofagreab-decrease'-inthenumber of specimens of S. smithii in this disi trict is certain,- dwh a’te.ve r may, be .the cause ltd which v tve -may l attribute it.” A great, nuraber'/of .the forest-dwelling species l in/ New” Zealand were 'nocturnal in ■tlicir'ihabitsl '/These could only' be captured' by searching - the, flowers and foliage; of, shrubs; and trees by the aid of a powerful lantern, at night. r A| good, method-- ofrworking for- ■forest species was by means .of. a. careful scru- : tiny of tree-trunks.- The open lowlands in New Zealand were nob nearly so productive in insect-life as the fori f&ts.,. The -original flora, of;these locali-]

ties was, however, undergoing rapid alteration, owing, to the extension of settlement, though', the. changes were not so groat' in those, places wnero tn© complete Clearing of .extensive forests was proceeding-, Thei; tussock-covered plains in many pprts.'of the boutlx Isand remained ..practically * m fheip_primitive condition) though' the periodical burning of l the native grasses must mi©-. stroy immense numbers*, of insects, and would no dopb.t ultimately fead to theextinctioii .of many species. ' j\lountam ■collecting wag.probably the niost interesting class of. collecting, we. had .. in N ow. Zealand, but'it was not, to his "mind, nearly so important a branen , of work for this generation, of naturalists.; as the. collection..of specimens,in ,the.lowland ’’forests. Mountains of less thaiii 3000 feet in height were in places extensively used for agricul-j tural purposes, and the flora of these localities would consequently be subf ject to modification and extinction, insect fauna sharing a. similar fatop but the flora' of the higher was not likely to be much by cultivation, and hence he considered that the ‘ imniediafo formation' of ‘ coll 'lections "of flip'higher alpine ’ species, although of igreat .interest, was not soj important* to the interests of futurej science as the preservation, of .examplesof - - species , inhabiting the rapidly, dis-; appearing- forests. Nevertheless,- -col-i lections of- the* mountain, species in New: Zealand W6CO-.gr.eat desidprata. After giving- -if 'short account of . such experiences qf ‘ mountain'collecting as he- had ■ ehjoyad, Mr 'coiichld--ed . his ad'dtess -in these words : —“AI-i though it' is*/ Very- pfobable' that I aui inclined to , overrate 'the : .importance of natural ' his'tlary studies ' '‘generally, yei there are still' some,, even amongst scientific men, who ,1 fear are ; inclined to undervalue the. work accomplished by collectors. It-should, however, bq -borne in mind that many of l our - most' sue), cessful philosophers ■ and Scientists have sprung from the ranks of mei‘6,collectors, and have not 5 all Been 'produced by the more orthodox, though less -original, method's of J the universities ..and kindred, institutions.;:; . JJanvin ... may he fairly tjpe.of man .whose linparMr6le3~ahilitles as a naturalistnnd philosopher, were largely due. tq_ Vliis harly, experiences, firstly' iis. a collector J and 'subsoquehtly as'an observer-,jn .the field. 'His marvellous powers were certainly,. ; not > acquired, by' ; book-learning only, or by the, passing of examinations; -but almost 1 entirely- by original research' and patient- 1 study- in the •field.-‘-There is no denying the' fact ..that; Darwin 'discovered'the most far-vcnchrng' law that lias yet; boon discovered iu:.cdnjice(ion with biologicald science—i.q,, 1 tile fpvinciplo/ of, natural sdlecfcicin 'of ‘the’ survival of the’, fittest; a discovery .which "is only equalled by that of Sir Isaac' Newton- in ; a«tronolny.V .The fact-that Dart wfu! began his scientific career'as-a'col-j : lector of beetle's-will;'-1 trust, : be'taken by the society as some excuse for . the ; amount'; of ."time ’. 1, 'have occupied ‘in delivering ■an addr.tes, oil • entomological - collecting, in t Not/ 'Zealand,” ■)rMi*..liiid-* : .son,- was . applauHcd - for''lds; address/ which' was .‘illustrated; .by‘ specimens. - ; A. vote-of itbaiiiks was accorded 1 -to eMr Hudson. -for..liis -address -on-the -motion 1 of Mr W. T. 1 1. Travers, seconded by i Sir James Hector) - I