One of two individuals observed near a cluster of yuccas (the other individual is here: https://www.inaturalist.org/observations/42495696). This is a known location for this species, east of its main range (Marks, 2018, Butterflies of Louisiana)

Today, we went into the forest for an extended walk. We stopped at a few places to collect some data. Locations of these observations approximate, and ID's lacking -- got some work to do!
https://www.inaturalist.org/journal/sambiology/25760-costa-rica-wow

The left-side individual, with a Cassius Blue from the LRGV for comparison.

I have a theory about IDing this species from Cassius Blue:

Note the arrangement of dark marks underlined in pink:

For Marine, the dark block in the fourth inter-veinal wedge (the wedge labeled with a green "4") is usually in-line with the outer three blocks; this individual Marine has a slight "uptick" in the 3rd inter-veinal block just before it meets the 4th, but the 4th inter-veinal block is still mostly in-line with the others.

For Cassius, the 4th inter-veinal block is sharply offset basally such that its upper/outer corner touches (or is separated from) the inner/lower corner of the 3rd inter-venial block.

I have been checking this feature for many years, and I feel that it is a very reliable means of distinguishing between the two taxa.

A totally remarkable aberrant. Seen on a butterfly field trip seminar I was leading with 9 people. ID is based on size (very small for greater frit), wing shape (round), and likelihood (normal ones very common in this meadow and the only fritillary we saw. There were a couple egleis on the walk in, but on rocky trail. This was in wet meadow which is mormon frit zone). I'm confident this was an aberrant mormon fritillary. A stunning one, too - top side and under

I am looking at the white mass under the wing of the planthopper. Although I see no record of this moth in California, it is the only possibility that I could find that looks like this and that infects planthoppers.