'cf.' is short for the latin word 'confer' that refers to 'like'. In taxonomy it is used in the sense of 'the specimen looks like this species but is probably a different species'.

The specimen in the picture resembles the European species D. ornata. American taxonomists lump all colour variants to one species: D. minuta. But European taxonomists consider D. minuta as a different species to D. ornata...

In this specific case, due to different opinions between European and American taxonomist wrt closely resembling dicyrtomid specimens, this specimen can be called
1. Dicyrtomina cf. ornata (the European way).
2. Dicyrtomina minuta forma ornata (the American way).

I'm afraid your clarification left me more confused than before. :)

Is this in the right place or not?

We have both a minuta and an ornata page in the Guide. If I understand you correctly, all of the images currently in ornata should actually be on a "forma ornata" page under minuta (if, that is, we want to be consistent with American taxonomy). Is that correct--or have I gotten things hopelessly mixed up?

To be consistent with current American authors taxonomy you can put all American 'D. ornata' under D. minuta forma ornata.
As long as the ongoing revision of the northern American Collembola is not published, American lookalike specimens of the European D. ornata can be placed here as D. minuta forma ornata. Pls, note that taxonomy is a dynamic discipline. Opinions may change in the future...

I've posted the suggested change in the Taxonomy Proposals forum to give others a chance to comment. If no one objects, I'll make a "forma ornata" page and move these images there.

the two with IDs of "D. saundersi, in the U.S. called D. minuta" and "D. minuta (var. labellei)". Should they have subspecies/forma pages?

D. saundersi could be placed under D. minuta forma saundersi to be consistent with American authors taxonomy, and to take into account it is a lookalike of the European D. saundersi, therefore possibly the same. But the latter has to be confirmed by a revison of all American and European lookalike specimens. Therefore, for the time being, I would suggest to use D. minuta forma saundersi for D. saundersi lookalike specimens from northern America.

With respect to var. labellei. This is a different matter. This variant was originally described as a separate species from New York by Maynard in 1951. But has been lumped currently as synonym to D. minuta. I use the label 'var. labellei' for specimens of D. minuta that match with the original description of D. labellei.

To summarise:
the 'European D. minuta' = the yellow Dicyrtomina with just one dorsal black patch on its bud, while
the 'American D. minuta' = the European D. minuta (with only one dorsal black patch on its bud) + the European D. ornata lookalike (with extra black ornamentation/pigmentation laterally) + the European D. saundersi lookalike (with a multibarred cross patch on its bud) + the American D. labellei lookalike (that looks like a very pale ornata).
Given ornata and saundersi are distinct colour forms, such patterned American specimens could be 'cataloged' as forma ornata and forma saundersi of D. minuta.