I am leaning toward Stripe Tail, but I am definitely no expert. Either way, I would venture to guess that is most likely the culprit in San Diego. We had a family dog we believe got stung by a bark here in Vegas, and he pretty much slept, some vomiting, and had no appetite for about 3 days. I didn't notice any major swelling, but we took him to the vet, and the vet too had no idea. Shortly thereafter we started finding a few scorpions around the house. I remembered when a friend of mine got tagged as a kid, and he too had very similar symptoms. Thus we figured that was most likely the cause.

Sorry to hear about your pooch. Hopefully he is ok now or on the road to recovery.