You are looking at the HTML representation of the XML format.
HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information.
<?xml version="1.0"?>
<api>
  <query>
    <pages>
      <page pageid="225238" ns="0" title="Balistes capriscus">
        <images>
          <im ns="6" title="File:GreyTriggerfish.JPG" />
        </images>
      </page>
      <page pageid="625244" ns="0" title="Lymantria (Spinotria) grauli" />
      <page pageid="441838" ns="0" title="Lasioglossum atriventre" />
      <page pageid="381742" ns="0" title="Paracymus ellipsis" />
      <page pageid="73805" ns="0" title="Galearia (Eucharitidae)" />
      <page pageid="584932" ns="0" title="Nyctemera (Nyctemera) mesolychna" />
      <page pageid="484056" ns="0" title="Listriodon" />
      <page pageid="106017" ns="0" title="Incarvillea arguta">
        <images>
          <im ns="6" title="File:Commons-logo.svg" />
          <im ns="6" title="File:Incarvillea arguta 2.jpg" />
        </images>
      </page>
      <page pageid="447588" ns="0" title="Youtang Yang" />
      <page pageid="262135" ns="0" title="Convolvulus althaeoides">
        <images>
          <im ns="6" title="File:Convolvulus althaeoides01.jpg" />
        </images>
      </page>
    </pages>
  </query>
</api>