Australian Tortoise Beetles are commonly found in this park. My recollection is that the larva was *much* larger than the adult tortoise beetles, but maybe that's normal for beetles? I don't know. Looking around for descriptions of the larvae I found this from UC Davis:

The larvae of both tortoise beetle species superficially resemble caterpillars (larvae of butterflies and moths) or larvae of sawflies but can be distinguished by their appendages. Caterpillars, larvae of leaf beetles (tortoise beetles) and sawflies all have three pairs of true jointed legs on their thorax. Caterpillars and sawfly larvae also have several pairs of prolegs (fleshy, round, leg-like protuberances) on their abdomen. By contrast, tortoise beetle larvae do not have any prolegs on their abdomen.

Trachymela sloanei larvae are dark green to reddish brown with a black head and prothoracic shield (black area on the top and sides of the first segment behind the head). Chrysophtharta m-fuscum larvae are lighter greenish gray with a black head. Larval color in both species resembles that of host foliage, camouflaging the larvae. Larvae develop through four immature stages before pupating beneath loose bark, or they drop from the canopy to pupate in the soil or litter around the base of host trees. During warm weather, development time from egg to adult may be as short as 5 weeks. There are several generations per year from late winter through fall.

Trachymela sloanei larvae and adults hide under loose bark during the day and feed primarily at night. Also, they may be concentrated high in the tree, so determining the cause of damage may be difficult. If no leaf-feeding adults or larvae are observed on foliage, search beneath loose bark where adults, egg masses, larvae, and possibly pupae can be observed and collected for identification by your local county department of agriculture or University of California Cooperative Extension office.