Subfamilies are missing in the taxon hierarchy in Volume 3

[jocelynpender]

Examples:
In the print volume, Alnus is a genus in Family Betulaceae, subfamily Betuloideae
Alnus.xml:
---
<taxon_identification status="ACCEPTED">
<taxon_name rank="family" authority="Gray" date="unknown">betulaceae</taxon_name>
<taxon_name rank="genus" authority="Miller" date="1754">ALNUS</taxon_name>
<place_of_publication>
<publication_title>Gard. Dict. Abr. ed.</publication_title>
<place_in_publication>4. 1754</place_in_publication>
</place_of_publication>
<taxon_hierarchy>family betulaceae;genus ALNUS</taxon_hierarchy>