Maybe the striped oakworm caterpillar?

They do look like one of the oakworms, the larva of a moth. If control is needed an early stage material to use is Bacillus thuringiensis -Kurstaki with Neem Oil products for later life stages and maybe pyrethrin sprays if the infestation is too large.
While asthetically they may be undesirable they really do little permanent harm to your tree since the tree is now getting ready to drop those leaves anyway.

More likely the Red-humped Appleworm, Schizura concinna. This is the species of hump-back caterpillars that is more likely to be found on members of the Rosaceae family, including Serviceberry.

Whatever they are, they're too old for Bt to work.

Disrupt them.
Flick into soapy water.
Act now.

THANKS for the replies so far. I realize I may not find something exact, but so far I cannot find that "perfect" match. I have included a link to another better picture of just one of them as well. I have also contacted out local Virginia Cooperative Extension Office to see if they can help identify. THANKS again.
-- Jim

Here is a link that might be useful: {{gwi:1189068}}

Look at datana ministra...yellownecked caterpillar. Whatever they are, treatment is the same, I believe. Sometimes they're hard to identify because they look different at certain stages. I like to know what the egg or egg sack looks like in case I want to dispose of them early.

See the link, esp. photos 6 and 7. Even though the link says you find them on oaks, it looks similar to your guy. I guess I'm just curious, too.

Here is a link that might be useful: link

We all like a good mystery! Another factor that makes ID challenging is that caterpillars (some more so than others) change in appearance as they continue to advance through instars. Each time they shed their skin, they might look a little different. Schizura concinna, for example, start out with a black head capsule, which changes to red in the final instars. Some cats change so much that it's difficult to believe that they are the same insect you looked at 20 minutes prior, before they shed their skin.

The attached link has images of several cool cats, but scroll down to the bottom (plates 8010) and you'll find images of a mature S. concinna and a younger instar. Interesting, huh?

One clue I find valuable in the ID of caterpillars is the food source. Though the other caterpillars mentioned above might be found on a very wide range of plants, they are very common on maples, oaks, elms, hickories, etc. Schizura, also found on a wide range of host plants, are most commonly found on apples, pears, crabapples, serviceberry, and other members of the Rosaceae family.

Here is a link that might be useful: Some caterpillar pictures

I think I will go with the Yellownecked Caterpillar (http://ento.psu.edu/extension/factsheets/yellownecked-caterpillar). In looking at some images on the web, I have found some good ones of their clusters with almost the exact colorings as the ones I found. And as was pointed out, they have changed over the past few days, again looking like the Yellownecked Caterpillars. And even though they are not pose a great threat to the tree (since defoliation is confined to the late part of the growing season, little damage is caused to the tree), I have read to get rid of them, which I am now in the process of doing. THANKS all for the input.

Glad to see this mystery come to a close. Be on the look out for their egg sacs too.