Mystery caterpillar; please help identify

[Pierre A Plauzoles]

Hello.

I was up in the Angeles National Forest today and saw a strange looking 
hatchling (?) caterpillar about 4 mm long on bigleaf maple (Acer 
macrophyllum).  It has no spines and seems not to have hair pencils, 
although it does have two hair tufts (so far, not four like tussock 
moths).  Unlike the tussock moths I have seen so far, the body and hair 
are jet black.  The hair (I use the term to distinguish from spines) are 
irregular in both length and straightness, although there are two 
distinct lengths of hair: short (~1 mm) in the tufts and also dispersed 
throughout the body, and long (3 mm+), quite of the long hair being 
somewhat crooked.  The tufts are quite dense, and directly in front of 
the first one is a dull yellowish gray dorsocentral dot; another brighter 
one is located over the second to last pair of false legs.  The first dot 
goes about two thirds of the back second dot going all the way across the 
back.

Like I said, it was observed in the Angeles National Forest on Acer 
macropyllum.  The location is along SR 2 about 5.3 miles north of I-210 
at about 2850 feet elevation.  This is on the south side of the San 
Gabriel Mountains.

If anyone has any ideas, I would appreciate some pointers as to where to 
find some information on this critter.

Thank you all.
-- 
Pierre Plauzoles   ae779 at lafn.org
Canoga Park, California