There are four Categories to label the content:

• Taxa: a tree structured species list. The content can be tagged only with taxa listed here. The current list comprises all of the valid taxa for the Palaeartic region plus some unresolved unvailable names. Other taxa can be added if some user wants it. For example, as I was interested in having a Myrmelachista specimen identified, I had to add "Myrmelachista" to the Formicinae subfamiliy, although it's not present in the Palaeartic (by now!).
• Geozones: to deal with geographic distributions, and validity of the keys in a given geozone. The different geozones have a tree structure. For example, inside "Iberian Peninsula"  we have added three more categories "Andorra", "Portugal" and "Spain".
• Sections: represent the different bullet points or chapters the content can be referred to. Examples are "Worker", "Distribution", "Biology", etc.
• Body Parts: available only for images. It is used in the Images Comparison Tool to filter the same part of the body to compare. Examples are "Head Frontal view" or "Scape dorsal view"

One example. If you want to add the images of a Camponotus vagus worker, first you have to add an specimen, and then label it as "camponotus vagus" in the taxa category and as "worker" in the section category. Adding this categories to the content is quite straightforward and in most cases is a one-click issue. We'll deal with it later on.

If you're a visitor, these categories do not affect you and are totally transparent, olthough you'll find them everywhere when searching or managing lists.