▁is ▁generally ▁flat ▁with ▁rolling ▁mountains ▁and ▁plate aus . ▁ ▁In ▁ 1 9 2 3 , ▁they ▁were ▁the ▁last ▁eth nic ▁group ▁to ▁be ▁conquer ed ▁by ▁the ▁American ▁colonial ists . ▁Before , ▁they ▁had ▁no ▁collect ive ▁name . ▁Instead , ▁they ▁referred ▁to ▁themselves ▁based ▁on ▁their ▁residence ▁or ▁whether ▁they ▁lived : ▁up stream ▁( Im and aya ) ▁or ▁down stream ▁( Im all od ). ▁At ▁present , ▁they ▁are ▁commonly ▁known ▁as ▁Is neg s , ▁which ▁came ▁from ▁an ▁I loc ano ▁word ▁it neg ▁that ▁means ▁In hab itants ▁of ▁the ▁T in eg ▁River . ▁Some ▁of ▁them , ▁however , ▁still ▁call ▁themselves ▁as ▁Ap aya os . ▁Major ity ▁of ▁them ▁live ▁along ▁the ▁Ap ay ao ▁River - Ab ul og ▁River , ▁M atal ag ▁River , ▁and ▁the ▁small ▁rivers ▁on ▁the ▁hills ides ▁of ▁I loc os ▁Norte ▁and ▁Ab ra . ▁ ▁Because ▁there ▁was ▁no ▁political ▁or ▁w ard ▁system , ▁the ▁kin ship ▁groups ▁and ▁family ▁cl ans ▁became ▁the ▁central ▁social ▁organizations ▁and ▁were ▁usually ▁led ▁by ▁the ▁hus b ands . ▁Pol yg amy ▁is ▁allowed , ▁but ▁depends ▁on ▁the ▁capacity ▁of ▁the ▁husband ▁to ▁support ▁the ▁family . ▁Like ▁other ▁eth nic ▁groups , ▁they ▁also ▁follow ▁a ▁lot ▁of ▁tab o os . ▁These ▁tab o os ▁vary ▁from ▁place ▁to ▁place . ▁A ▁pre gn ant ▁woman , ▁for ▁example , ▁is ▁disc ou rag