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  <xsd:element abstract="true" id="istr_statement-statement-note-11-income-taxes-tables" name="statement-statement-note-11-income-taxes-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-12-commitments-and-contingencies-commitments-to-extend-credit-details" name="statement-statement-note-12-commitments-and-contingencies-commitments-to-extend-credit-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-12-commitments-and-contingencies-summary-of-acl-on-unfunded-loan-commitments-details" name="statement-statement-note-12-commitments-and-contingencies-summary-of-acl-on-unfunded-loan-commitments-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
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  <xsd:element abstract="true" id="istr_statement-statement-note-13-leases-future-minimum-lease-payment-details" name="statement-statement-note-13-leases-future-minimum-lease-payment-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-13-leases-quantitative-information-regarding-operating-leases-details" name="statement-statement-note-13-leases-quantitative-information-regarding-operating-leases-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-13-leases-tables" name="statement-statement-note-13-leases-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-2-business-combinations-schedule-of-business-combination-information-details" name="statement-statement-note-2-business-combinations-schedule-of-business-combination-information-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-2-business-combinations-schedule-of-pcd-loans-acquired-details" name="statement-statement-note-2-business-combinations-schedule-of-pcd-loans-acquired-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-2-business-combinations-tables" name="statement-statement-note-2-business-combinations-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-3-earnings-per-common-share-antidilutive-securities-details" name="statement-statement-note-3-earnings-per-common-share-antidilutive-securities-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-3-earnings-per-common-share-earnings-per-share-details" name="statement-statement-note-3-earnings-per-common-share-earnings-per-share-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-3-earnings-per-common-share-tables" name="statement-statement-note-3-earnings-per-common-share-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-4-investment-securities-amortized-cost-and-fair-value-of-investment-securities-classified-as-afs-details" name="statement-statement-note-4-investment-securities-amortized-cost-and-fair-value-of-investment-securities-classified-as-afs-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-4-investment-securities-amortized-cost-and-fair-value-of-investment-securities-classified-as-htm-details" name="statement-statement-note-4-investment-securities-amortized-cost-and-fair-value-of-investment-securities-classified-as-htm-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-4-investment-securities-contractual-maturity-details" name="statement-statement-note-4-investment-securities-contractual-maturity-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-4-investment-securities-sales-of-investments-classified-as-afs-details" name="statement-statement-note-4-investment-securities-sales-of-investments-classified-as-afs-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-4-investment-securities-summary-of-continuous-unrealized-loss-position-for-securities-classified-as-afs-details" name="statement-statement-note-4-investment-securities-summary-of-continuous-unrealized-loss-position-for-securities-classified-as-afs-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-4-investment-securities-summary-of-continuous-unrealized-loss-position-for-securities-classified-as-htm-details" name="statement-statement-note-4-investment-securities-summary-of-continuous-unrealized-loss-position-for-securities-classified-as-htm-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-4-investment-securities-tables" name="statement-statement-note-4-investment-securities-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-5-loans-and-allowance-for-credit-losses-aging-analysis-of-loans-details" name="statement-statement-note-5-loans-and-allowance-for-credit-losses-aging-analysis-of-loans-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-5-loans-and-allowance-for-credit-losses-allowance-for-loan-losses-details" name="statement-statement-note-5-loans-and-allowance-for-credit-losses-allowance-for-loan-losses-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-5-loans-and-allowance-for-credit-losses-loan-portfolio-by-category-and-credit-quality-indicator-details" name="statement-statement-note-5-loans-and-allowance-for-credit-losses-loan-portfolio-by-category-and-credit-quality-indicator-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-5-loans-and-allowance-for-credit-losses-loans-to-related-parties-details" name="statement-statement-note-5-loans-and-allowance-for-credit-losses-loans-to-related-parties-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-5-loans-and-allowance-for-credit-losses-schedule-of-nonaccrual-loans-details" name="statement-statement-note-5-loans-and-allowance-for-credit-losses-schedule-of-nonaccrual-loans-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-5-loans-and-allowance-for-credit-losses-summary-of-loans-by-categories-details" name="statement-statement-note-5-loans-and-allowance-for-credit-losses-summary-of-loans-by-categories-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-5-loans-and-allowance-for-credit-losses-tables" name="statement-statement-note-5-loans-and-allowance-for-credit-losses-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-6-goodwill-and-other-intangible-assets-amortization-schedule-for-core-deposit-intangible-assets-details" name="statement-statement-note-6-goodwill-and-other-intangible-assets-amortization-schedule-for-core-deposit-intangible-assets-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-6-goodwill-and-other-intangible-assets-core-deposit-intangible-assets-details" name="statement-statement-note-6-goodwill-and-other-intangible-assets-core-deposit-intangible-assets-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-6-goodwill-and-other-intangible-assets-schedule-of-goodwill-details" name="statement-statement-note-6-goodwill-and-other-intangible-assets-schedule-of-goodwill-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-6-goodwill-and-other-intangible-assets-tables" name="statement-statement-note-6-goodwill-and-other-intangible-assets-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-7-stockholders-equity-accumulated-other-comprehensive-income-loss-details" name="statement-statement-note-7-stockholders-equity-accumulated-other-comprehensive-income-loss-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-7-stockholders-equity-tables" name="statement-statement-note-7-stockholders-equity-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-8-stockbased-compensation-schedule-of-restricted-stock-activity-details" name="statement-statement-note-8-stockbased-compensation-schedule-of-restricted-stock-activity-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-8-stockbased-compensation-schedule-of-stock-option-activity-details" name="statement-statement-note-8-stockbased-compensation-schedule-of-stock-option-activity-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-8-stockbased-compensation-tables" name="statement-statement-note-8-stockbased-compensation-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-9-derivative-financial-instruments-offsetting-of-derivative-instruments-details" name="statement-statement-note-9-derivative-financial-instruments-offsetting-of-derivative-instruments-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-9-derivative-financial-instruments-schedule-of-derivatives-instruments-details" name="statement-statement-note-9-derivative-financial-instruments-schedule-of-derivatives-instruments-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-note-9-derivative-financial-instruments-tables" name="statement-statement-note-9-derivative-financial-instruments-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="istr_statement-statement-significant-accounting-policies-policies" name="statement-statement-significant-accounting-policies-policies" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
</xsd:schema>
