第7章

haveread，sufficientstressdoesnotappeartohavebeenlaidontheelasticityofthespine：sosuddenaspringcouldnotbetheresultofsimplemuscularcontraction，withouttheaidofsomemechanicalcontrivance。

OnseveraloccasionsIenjoyedsomeshortbutmostpleasantexcursionsintheneighbouringcountry。OnedayIwenttotheBotanicGarden，wheremanyplants，wellknownfortheirgreatutility，mightbeseengrowing。

Theleavesofthecamphor，pepper，cinnamon，andclovetreesweredelightfullyaromatic；andthebread-fruit，thejaca，andthemango，viedwitheachotherinthemagnificenceoftheirfoliage。ThelandscapeintheneighbourhoodofBahiaalmosttakesitscharacterfromthetwolattertrees。Beforeseeingthem，Ihadnoideathatanytreescouldcastsoblackashadeontheground。

BothofthembeartotheevergreenvegetationoftheseclimatesthesamekindofrelationwhichlaurelsandholliesinEnglanddotothelightergreenofthedeciduoustrees。Itmaybeobserved，thatthehouseswithinthetropicsaresurroundedbythemostbeautifulformsofvegetation，becausemanyofthemareatthesametimemostusefultoman。Whocandoubtthatthesequalitiesareunitedinthebanana，thecocoa-nut，themanykindsofpalm，theorange，andthebread-fruittree？

DuringthisdayIwasparticularlystruckwitharemarkofHumboldt’s，whooftenalludesto“thethinvapourwhich，withoutchangingthetransparencyoftheair，rendersitstintsmoreharmonious，andsoftensitseffects。”

ThisisanappearancewhichIhaveneverobservedinthetemperatezones。

Theatmosphere，seenthroughashortspaceofhalforthree-quartersofamile，wasperfectlylucid，butatagreaterdistanceallcolourswereblendedintoamostbeautifulhaze，ofapaleFrenchgrey，mingledwithalittleblue。Theconditionoftheatmospherebetweenthemorningandaboutnoon，whentheeffectwasmostevident，hadundergonelittlechange，exceptinginitsdryness。Intheinterval，thedifferencebetweenthedewpointandtemperaturehadincreasedfrom7。5to17degs。

OnanotheroccasionIstartedearlyandwalkedtotheGavia，ortopsailmountain。Theairwasdelightfullycoolandfragrant；andthedropsofdewstillglitteredontheleavesofthelargeliliaceousplants，whichshadedthestreamletsofclearwater。Sittingdownonablockofgranite，itwasdelightfultowatchthevariousinsectsandbirdsastheyflewpast。

Thehumming-birdseemsparticularlyfondofsuchshadyretiredspots。WheneverIsawtheselittlecreaturesbuzzingroundaflower，withtheirwingsvibratingsorapidlyastobescarcelyvisible，Iwasremindedofthesphinxmoths：

theirmovementsandhabitsareindeedinmanyrespectsverysimilar。

Followingapathway，Ienteredanobleforest，andfromaheightoffiveorsixhundredfeet，oneofthosesplendidviewswaspresented，whicharesocommononeverysideofRio。Atthiselevationthelandscapeattainsitsmostbrillianttint；andeveryform，everyshade，socompletelysurpassesinmagnificenceallthattheEuropeanhaseverbeheldinhisowncountry，thatheknowsnothowtoexpresshisfeelings。ThegeneraleffectfrequentlyrecalledtomymindthegayestsceneryoftheOpera-houseorthegreattheatres。Ineverreturnedfromtheseexcursionsempty-handed。ThisdayIfoundaspecimenofacuriousfungus，calledHymenophallus。MostpeopleknowtheEnglishPhallus，whichinautumntaintstheairwithitsodioussmell：this，however，astheentomologistisaware，is，tosomeofourbeetlesadelightfulfragrance。Sowasithere；foraStrongylus，attractedbytheodour，alightedonthefungusasIcarrieditinmyhand。Wehereseeintwodistantcountriesasimilarrelationbetweenplantsandinsectsofthesamefamilies，thoughthespeciesofbotharedifferent。Whenmanistheagentinintroducingintoacountryanewspecies，thisrelationisoftenbroken：asoneinstanceofthisImaymention，thattheleavesofthecabbagesandlettuces，whichinEnglandaffordfoodtosuchamultitudeofslugsandcaterpillars，inthegardensnearRioareuntouched。

DuringourstayatBrazilImadealargecollectionofinsects。AfewgeneralobservationsonthecomparativeimportanceofthedifferentordersmaybeinterestingtotheEnglishentomologist。ThelargeandbrilliantlycolouredLepidopterabespeakthezonetheyinhabit，farmoreplainlythananyotherraceofanimals。Ialludeonlytothebutterflies；forthemoths，contrarytowhatmighthavebeenexpectedfromtheranknessofthevegetation，certainlyappearedinmuchfewernumbersthaninourowntemperateregions。

IwasmuchsurprisedatthehabitsofPapilioferonia。Thisbutterflyisnotuncommon，andgenerallyfrequentstheorange-groves。Althoughahighflier，yetitveryfrequentlyalightsonthetrunksoftrees。Ontheseoccasionsitsheadisinvariablyplaceddownwards；anditswingsareexpandedinahorizontalplane，insteadofbeingfoldedvertically，asiscommonlythecase。ThisistheonlybutterflywhichIhaveeverseen，thatusesitslegsforrunning。Notbeingawareofthisfact，theinsect，morethanonce，asIcautiouslyapproachedwithmyforceps，shuffledononesidejustastheinstrumentwasonthepointofclosing，andthusescaped。Butafarmoresingularfactisthepowerwhichthisspeciespossessesofmakinganoise。[6]Severaltimeswhenapair，probablymaleandfemale，werechasingeachotherinanirregularcourse，theypassedwithinafewyardsofme；andIdistinctlyheardaclickingnoise，similartothatproducedbyatoothedwheelpassingunderaspringcatch。Thenoisewascontinuedatshortintervals，andcouldbedistinguishedatabouttwentyyards’distance：Iamcertainthereisnoerrorintheobservation。

IwasdisappointedinthegeneralaspectoftheColeoptera。Thenumberofminuteandobscurelycolouredbeetlesisexceedinglygreat。[7]ThecabinetsofEuropecan，asyet，boastonlyofthelargerspeciesfromtropicalclimates。Itissufficienttodisturbthecomposureofanentomologist’smind，tolookforwardtothefuturedimensionsofacompletecatalogue。

Thecarnivorousbeetles，orCarabidae，appearinextremelyfewnumberswithinthetropics：thisisthemoreremarkablewhencomparedtothecaseofthecarnivorousquadrupeds，whicharesoabundantinhotcountries。

IwasstruckwiththisobservationbothonenteringBrazil，andwhenI

sawthemanyelegantandactiveformsoftheHarpalidaere-appearingonthetemperateplainsofLaPlata。DotheverynumerousspidersandrapaciousHymenopterasupplytheplaceofthecarnivorousbeetles？Thecarrion-feedersandBrachelytraareveryuncommon；ontheotherhand，theRhyncophoraandChrysomelidae，allofwhichdependonthevegetableworldforsubsistence，arepresentinastonishingnumbers。Idonothererefertothenumberofdifferentspecies，buttothatoftheindividualinsects；foronthisitisthatthemoststrikingcharacterintheentomologyofdifferentcountriesdepends。TheordersOrthopteraandHemipteraareparticularlynumerous；

aslikewiseisthestingingdivisionoftheHymenopterathebees，perhaps，beingexcepted。Aperson，onfirstenteringatropicalforest，isastonishedatthelaboursoftheants：well-beatenpathsbranchoffineverydirection，onwhichanarmyofnever-failingforagersmaybeseen，somegoingforth，andothersreturning，burdenedwithpiecesofgreenleaf，oftenlargerthantheirownbodies。

Asmalldark-colouredantsometimesmigratesincountlessnumbers。Oneday，atBahia，myattentionwasdrawnbyobservingmanyspiders，cockroaches，andotherinsects，andsomelizards，rushinginthegreatestagitationacrossabarepieceofground。Alittlewaybehind，everystalkandleafwasblackenedbyasmallant。Theswarmhavingcrossedthebarespace，divideditself，anddescendedanoldwall。Bythismeansmanyinsectswerefairlyenclosed；andtheeffortswhichthepoorlittlecreaturesmadetoextricatethemselvesfromsuchadeathwerewonderful。Whentheantscametotheroadtheychangedtheircourse，andinnarrowfilesreascendedthewall。Havingplacedasmallstonesoastointerceptoneofthelines，thewholebodyattackedit，andthenimmediatelyretired。Shortlyafterwardsanotherbodycametothecharge，andagainhavingfailedtomakeanyimpression，thislineofmarchwasentirelygivenup。Bygoinganinchround，thefilemighthaveavoidedthestone，andthisdoubtlesswouldhavehappened，ifithadbeenoriginallythere：buthavingbeenattacked，thelion-heartedlittlewarriorsscornedtheideaofyielding。

Certainwasp-likeinsects，whichconstructinthecornersoftheverandahsclaycellsfortheirlarvae，areverynumerousintheneighbourhoodofRio。Thesecellstheystufffullofhalf-deadspidersandcaterpillars，whichtheyseemwonderfullytoknowhowtostingtothatdegreeastoleavethemparalysedbutalive，untiltheireggsarehatched；andthelarvaefeedonthehorridmassofpowerless，half-killedvictims——asightwhichhasbeendescribedbyanenthusiasticnaturalist[8]ascuriousandpleasing！IwasmuchinterestedonedaybywatchingadeadlycontestbetweenaPepsisandalargespiderofthegenusLycosa。Thewaspmadeasuddendashatitsprey，andthenflewaway：thespiderwasevidentlywounded，for，tryingtoescape，itrolleddownalittleslope，buthadstillstrengthsufficienttocrawlintoathicktuftofgrass。Thewaspsoonreturned，andseemedsurprisedatnotimmediatelyfindingitsvictim。

Itthencommencedasregularahuntaseverhounddidafterfox；makingshortsemicircularcasts，andallthetimerapidlyvibratingitswingsandantennae。Thespider，thoughwellconcealed，wassoondiscovered，andthewasp，evidentlystillafraidofitsadversary’sjaws，aftermuchmanoeuvring，inflictedtwostingsontheundersideofitsthorax。Atlast，carefullyexaminingwithitsantennaethenowmotionlessspider，itproceededtodragawaythebody。ButIstoppedbothtyrantandprey。[9]

Thenumberofspiders，inproportiontootherinsects，isherecomparedwithEnglandverymuchlarger；perhapsmoresothanwithanyotherdivisionofthearticulateanimals。Thevarietyofspeciesamongthejumpingspidersappearsalmostinfinite。Thegenus，orratherfamily，ofEpeira，isherecharacterizedbymanysingularforms；somespecieshavepointedcoriaceousshells，othersenlargedandspinytibiae。Everypathintheforestisbarricadedwiththestrongyellowwebofaspecies，belongingtothesamedivisionwiththeEpeiraclavipesofFabricius，whichwasformerlysaidbySloanetomake，intheWestIndies，webssostrongastocatchbirds。Asmallandprettykindofspider，withverylongfore-legs，andwhichappearstobelongtoanundescribedgenus，livesasaparasiteonalmosteveryoneofthesewebs。IsupposeitistooinsignificanttobenoticedbythegreatEpeira，andisthereforeallowedtopreyontheminuteinsects，which，adheringtothelines，wouldotherwisebewasted。Whenfrightened，thislittlespidereitherfeignsdeathbyextendingitsfrontlegs，orsuddenlydropsfromtheweb。AlargeEpeiraofthesamedivisionwithEpeiratuberculataandconicaisextremelycommon，especiallyindrysituations。Itsweb，whichisgenerallyplacedamongthegreatleavesofthecommonagave，issometimesstrengthenednearthecentrebyapairorevenfourzigzagribbons，whichconnecttwoadjoiningrays。Whenanylargeinsect，asagrasshopperorwasp，iscaught，thespider，byadexterousmovement，makesitrevolveveryrapidly，andatthesametimeemittingabandofthreadsfromitsspinners，soonenvelopsitspreyinacaselikethecocoonofasilkworm。

Thespidernowexaminesthepowerlessvictim，andgivesthefatalbiteonthehinderpartofitsthorax；thenretreating，patientlywaitstillthepoisonhastakeneffect。ThevirulenceofthispoisonmaybejudgedoffromthefactthatinhalfaminuteIopenedthemesh，andfoundalargewaspquitelifeless。ThisEpeiraalwaysstandswithitsheaddownwardsnearthecentreoftheweb。Whendisturbed，itactsdifferentlyaccordingtocircumstances：ifthereisathicketbelow，itsuddenlyfallsdown；