Spider mites? Treatment for them is to wash the foliage off, top and bottom, daily for 5-7 days. Spider mites don't like moist foliage.

Here is a link that might be useful: {{gwi:596832}}

Was instant messaging with an entomologist friend of mine and showed him your post...

Violetta: what are your thoughts on this? http://forums.gardenweb.com/forums/load/clematis/msg061027269390.html?1
Friend: completely orange is a pretty rare color scheme for aphids
Friend: but the main way to tell if they are aphids vs. somthing else is to look at them closely and see if they are sort of sedentary, with their little feeding beak stuck in the plant, vs. other orange insects, such as the nymph stage of milkweed bugs or mites - which tend to be pretty mobile
Violetta: and if they are something else?
Friend: the treatment might depend on what they are, but if we are dealing with only a few plants, wiping or blasting off the offending insects by hand tend to be the most effective and efficient method
Friend: what is the geographic range of that forum?
Friend: location is important for knowing which species they are
Friend: if they can take a digital image and send it to me, I could at least tell them what type of pest it is,
Friend: and then recommend what to do, at least for that type of pest
Friend: but again, wiping them off works for many different types of pest
Friend: it's less effective for those that 1) are coming in continuously from some source, or 2) develop and multiply very rapidly (eg. aphids)
Violetta: k, i'm posting a response now, thank you