This may also be Pepsis marginata, which looks very similar to Pespis grosso, and also occurs on Puerto Rico, but I guess it is very difficult to tell from just a photo.

Pepsis grossa is one of the largest species, with females reaching 30-51 mm.
Pepsis marginata is generally smaller than Pepsis grossa.

Cambalache State Forest, Puerto Rico, 16 January 2026