the malay archipelago-1-第35章

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The　other　species　to　which　I　have　to　direct　attention　is　the　Kallima　paralekta；　a　butterfly　of　the　same　family　group　as　our　Purple　Emperor；　and　of　about　the　same　size　or　larger。　Its　upper　surface　is　of　a　rich　purple；　variously　tinged　with　ash　colour；　and　across　the　forewings　there　is　a　broad　bar　of　deep　orange；　so　that　when　on　the　wing　it　is　very　conspicuous。　This　species　was　not　uncommon　in　dry　woods　and　thickets；　and　I　often　endeavoured　to　capture　it　without　success；　for　after　flying　a　short　distance　it　would　enter　a　bush　among　dry　or　dead　leaves；　and　however　carefully　I　crept　up　to　the　spot　I　could　never　discover　it　until　it　would　suddenly　start　out　again　and　then　disappear　in　a　similar　place。　If　at　length　I　was　fortunate　enough　to　see　the　exact　spot　where　the　butterfly　settled；　and　though　I　lost　sight　of　it　for　some　time；　I　would　discover　that　it　was　close　before　my　eyes；　but　that　in　its　position　of　repose　it　so　closely　resembled　a　dead　leaf　attached　to　a　twig　as　almost　certainly　to　deceive　the　eye　even　when　gazing　full　upon　it。　I　captured　several　specimens　on　the　wing；　and　was　able　fully　to　understand　the　way　in　which　this　wonderful　resemblance　is　produced。

The　end　of　the　upper　wings　terminates　in　a　fine　point；　just　as　the　leaves　of　many　tropical　shrubs　and　trees　are　pointed；　while　the　lower　wings　are　somewhat　more　obtuse；　and　are　lengthened　out　into　a　short　thick　tail。　Between　these　two　points　there　runs　a　dark　curved　line　exactly　representing　the　midrib　of　a　leaf；　and　from　this　radiate　on　each　side　a　few　oblique　marks　which　well　imitate　the　lateral　veins。　These　marks　are　more　clearly　seen　on　the　outer　portion　of　the　base　of　the　wings；　and　on　the　innerside　towards　the　middle　and　apex；　and　they　are　produced　by　striae　and　markings　which　are　very　common　in　allied　species；　but　which　are　here　modified　and　strengthened　so　as　to　imitate　more　exactly　the　venation　of　a　leaf。　The　tint　of　the　undersurface　varies　much；　but　it　is　always　some　ashy　brown　or　reddish　colour；　which　matches　with　those　of　dead　leaves。　The　habit　of　the　species　is　always　to　rest　on　a　twig　and　among　dead　or　dry　leaves；　and　in　this　position　with　the　wings　closely　pressed　together；　their　outline　is　exactly　that　of　a　moderately…sized　leaf；　slightly　curved　or　shrivelled。　The　tail　of　the　hind　wings　forms　a　perfect　stalk；　and　touches　the　stick　while　the　insect　is　supported　by　the　middle　pair　of　legs；　which　are　not　noticed　among　the　twigs　and　fibres　that　surround　it。　The　head　and　antennae　are　drawn　back　between　the　wings　so　as　to　be　quite　concealed；　and　there　is　a　little　notch　hollowed　out　at　the　very　base　of　the　wings；　which　allows　the　head　to　be　retracted　sufficiently。　All　these　varied　details　combine　to　produce　a　disguise　that　is　so　complete　and　marvellous　as　to　astonish　everyone　who　observes　it；　and　the　habits　of　the　insects　are　such　as　to　utilize　all　these　peculiarities；　and　render　them　available　in　such　a　manner　as　to　remove　all　doubt　of　the　purpose　of　this　singular　case　of　mimicry；　which　is　undoubtedly　a　protection　to　the　insect。

Its　strong　and　swift　flight　is　sufficient　to　save　it　from　its　enemies　when　on　the　wing；　but　if　it　were　equally　conspicuous　when　at　rest　it　could　not　long　escape　extinction；　owing　to　the　attacks　of　the　insectivorous　birds　and　reptiles　that　abound　in　the　tropical　forests。　A　very　closely　allied　species；　Kallima　inachis；　inhabits　India；　where　it　is　very　common；　and　specimens　are　sent　in　every　collection　from　the　Himalayas。　On　examining　a　number　of　these；　it　will　be　seen　that　no　two　are　alike；　but　all　the　variations　correspond　to　those　of　dead　leaves。　Every　tint　of　yellow；　ash；　brown；　and　red　is　found　here；　and　in　many　specimens　there　occur　patches　and　spots　formed　of　small　black　dots；　so　closely　resembling　the　way　in　which　minute　fungi　grow　on　leaves　that　it　is　almost　impossible　at　first　not　to　believe　that　fungi　have　gown　on　the　butterflies　themselves！

If　such　an　extraordinary　adaptation　as　this　stood　alone；　it　would　be　very　difficult　to　offer　any　explanation　of　it；　but　although　it　is　perhaps　the　most　perfect　case　of　protective　imitation　known；　there　are　hundreds　of　similar　resemblances　in　nature；　and　from　these　it　is　possible　to　deduce　a　general　theory　of　the　manner　in　which　they　have　been　slowly　brought　about。　The　principle　of　variation　and　that　of　〃natural　selection；〃　or　survival　of　the　fittest；　as　elaborated　by　Mr。　Darwin　in　his　celebrated　〃Origin　of　Species；〃　offers　the　foundation　for　such　a　theory；　and　I　have　myself　endeavoured　to　apply　it　to　all　the　chief　cases　of　imitation　in　an　article　published　in　the　〃Westminster　Review〃　for　1867；　entitled；　〃Mimicry；　and　other　Protective　Resemblances　Among　Animals；〃　to　which　any　reader　is　referred　who　wishes　to　know　more　about　this　subject。

In　Sumatra；　monkeys　are　very　abundant；　and　at　Lobo　Kaman　they　used　to　frequent　the　trees　which　overhang　the　guard…house；　and　give　me　a　fine　opportunity　of　observing　their　gambols。　Two　species　of　Semnopithecus　were　most　plentifulmonkeys　of　a　slender　form；　with　very　long　tails。　Not　being　much　shot　at　they　are　rather　bold；　and　remain　quite　unconcerned　when　natives　alone　are　present；　but　when　I　came　out　to　look　at　them；　they　would　stare　for　a　minute　or　two　and　then　make　off。　They　take　tremendous　leaps　from　the　branches　of　one　tree　to　those　at　another　a　little　lower；　and　it　is　very　amusing　when　a　one　strong　leader　takes　a　bold　jump；　to　see　the　others　following　with　more　or　less　trepidation；　and　it　often　happens　that　one　or　two　of　the　last　seem　quite　unable　to　make　up　their　minds　to　leap　until　the　rest　are　disappearing；　when；　as　if　in　desperation　at　being　left　alone；　they　throw　themselves　frantically　into　the　air；　and　often　go　crashing　through　the　slender　branches　and　fall　to　the　ground。

A　very　curious　ape；　the　Siamang；　was　also　rather　abundant；　but　it　is　much　less　bold　than　the　monkeys；　keeping　to　the　virgin　forests　and　avoiding　villages。　This　species　is　allied　to　the　little　long…　armed　apes　of　the　genus　Hylobates；　but　is　considerably　larger；　and　differs　from　them　by　having　the　two　first　fingers　of　the　feet　united　together；　nearly　to　the　endm　as　does　its　Latin　native；　Siamanga　syndactyla。　It　moves　much　more　slowly　than　the　active　Hylobates；　keeping　lower　down　in　trees；　and　not　indulging　in　such　tremendous　leaps；　but　it　is　still　very　active；　and　by　means　of　its　immense　long　arms；　five　feet　six　inches　across　in　an　adult　about　three　feet　high；　can　swing　itself　along　among　the　trees　at　a　great　rate。　I　purchased　a　small　one；　which　had　been　caught　by　the　natives　and　tied　up　so　tightly　as　to　hurt　it。　It　was　rather　savage　at　first；　and　tried　to　bite；　but　when　we　had　released　it　and　given　it　two　poles　under　the　verandah　to　hang　upon；　securing　it　by　a　short　cord；　running　along　the　pole　with　a　ring　so　that　it　could　move　easily；　it　became　more　contented；　and　would　swing　itself　about　with　great　rapidity。　It　ate　almost　any　kind　of　fruit　and　rice；　and　I　was　in　hopes　to　have　brought　it　to　England；　but　it　died　just　before　I　started。　It　took　a　dislike　to　me　at　first；　which　I　tried　to　get　over　by　feeding　it　constantly　myself。　One　day；　however；　it　bit　me　so　sharply　while　giving　it　food；　that　I　lost　patience　and　gave　it　rather　a　severe　beating；　which　I　regretted　afterwards；　as　from　that　time　it　disliked　me　more　than　ever。　It　would　allow　my　Malay　boys　to　play　with　it；　and　for　hours　together　would　swing　by　its　arms　from　pole　to　pole　and　on　to　the　rafters　of　the　verandah；　with　so　much　ease　and　rapidity；　that　it　was　a　constant　source　of　amusement　to　us。　When　I　returned　to　Singapore　it　attracted　great　attention；　as　no　one　had　seen　a　Siamang　alive　before；　although　it　is　not　uncommon　in　some　parts　of　the　Malay　peninsula。

As　the　Orangutan　is　known　to　inhabit　Sumatra；　and　was　in　fact　first　discovered　there；　I　made　many　inquiries　about　it；　but　none　of　the　natives　had　ever　heard　of　such　an　animal；　nor　could　I　find　any　of　the　Dutch　officials　who　knew　anything　about　it。　We　may　conclude；　therefore；　that　it　does　not　inhabit　the　great　forest　plains　in　the　east　of　Sumatra　where　one　would　naturally　expect　to　find　it；　but　is　probably　confined　to　a　limited　region　in　the　northwest　part　of　the　island　entirely　in　the　hands　of　native　rulers。　The　other　great　Mammalia　of　Sumatra；　the　elephant　and