Two very similar species of angle-winged katydid live aling the central California coast. According to J.R. Helfer's "How to Know the Grasshoppers, Crickets, Cockroaches, and their Allies" (1967), M. rhombifolium has a blunt "tooth" at the middle of the front margin of the pronotum, while M. californicum is shallowly emarginate at this location. At a large size, a clear indentation is visible along the leading edge of the pronotum.

It was found under the eaves at the visitors center, probably attracted to the light the night before.

A higher resolution photo can be found here:
https://www.flickr.com/photos/21529332@N08/20723562335/in/dateposted-public/