Thanks for your input everyone.
This is NOT pinworm. He passed a worm the other night (it is about 3 to 4 inches in length and thin as a thread.) He also passed what looked like fat rice -- although he hadn't eaten anything that looks like that--(maybe larva?) I have collected the worm in a jar to take to allopathic doc tomorrow am. Hopefully they will send it to the lab to determine exactly what it is, although I do not have that much faith in them.

Pannakkal, I think you may be correct. We did visit the zoo recently (4 to 5 weeks ago) and my son got quite dirty there. I suspect he may have acquired this infection there. However, we live in Florida and there are quite a few critters that enjoy our mild climate. It was about 2 weeks ago when he had the transient linear welts, low grade fever and very irritable. Now he only complains that his bottom is tender (it looks ok to me) and he says OUCH! now and then for no apparent reason. His head sweat severely when he slept a couple weeks ago and that has decreased significantly. His arms and legs seemed to be hurting, but that has improved as well. Maybe I should wait and see what happens. Or maybe a prophylaxis deworming would be in order.
Karen