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1、半翅目hemiptera(英文)简介Order-HEMIPTERA(Greek,hemi=half;pteron=wing)CommonNames:bugs,leafhoppers,cicadas,aphids,scaleinsects. Distribution:Cosmopolitan Suborders:Sternorrhyncha,Auchenorrhyncha,HeteropteraCharacteristicsTheforewingsofmanyhemipteranswhicharehardenednearthebase,butmembrano
2、usattheends.Thesewingsaretermedhemelytra(singular:hemelytron),byanalogywiththecompletelyhardenedelytraofbeetles.Theymaybeheld"roofwise"overthebody,orheldflatontheback,withtheendsoverlapping.Thehindwingsareentirelymembranousandareusuallyshorterthantheforewings.HabitatBecausethisord
3、erissodiverse,thehabitatsarewidelyvaried,Hemipteraincludesterrestrialandaquaticinsects,andmembersoftheordermaybefoundonplantsandanimals.Theyareabundantworldwide.DistributionThisisaverysuccessfulgroupofinsects,withabout80,000species,andfoundinterrestrialandaquaticenvironments,inclu
4、dingtheonlyknownmarine-pelagicinsects.AmonggroupsincludedinHemipteraarecicadas,aphids,planthoppers,leafhoppers,shieldbugs,assassinbugs,bedbugs,andothers.Whilemanyfeedonsapandotherplantmaterial,somefeedonanimalsources,suchasthehemolymphofotherarthropodsandthebloodofmammalsandbirds.
5、EconomicsignificanceHemipteransarevitallyimportantaspartoffoodchains,beingconsumedbycountlessvertebratesandinvertebrates.Andasoneofthefewandperhapsthemostimportantinsectgroupthathasadaptedtoaquaticenvironments,theyprovideanimportantsourceoffoodforfish,and,beingvoraciouspredators,h
6、elptocontrolmosquitoesduringthemosquito'saquaticlarvalstage.Whilemanyhemipterans,suchasaphidsandscaleinsects,aresignificantpestsofcropsandgardens,somepredatoryformsservetocontrolagriculturalpests.ClassificationMajorInfraordersorSuperfamiliesintheOrder:Aphidoidea-aphidsPentatomoide
7、a–shieldbugsGerromorpha–waterstriders,watercricketsCicadoidea-cicadasTingoidae–lacebugsCoccoidea–scaleinsects2.1数学归纳法及其应用(3)请问：用数学归纳法证明的一般步骤是什么？一、用数学归纳法证明整除问题注意：用数学归纳法证明多项式的整除问题。当n只出现在指数中时，采用加一“项”，再减去这一“项”的方法。这个“项”的构造应观察题目的具体特点，以有利于分段因式分解后，达到便于归纳假设成立的那个式子上“凑”的目的。注意：当n只出现在底数中时，采用把k
8、+1的幂展开后，分段组合，往归纳假设的n=k的式子上“凑”的方法。
