I am seeing more and more of this bug in my yard this year-;usually on the stems of clematis, but it's been on everything. It is light brown or grey, flat on the bottom,rounded top, like the letter D on it's side. Then, it has this whitish fluff coming out the behind. If you touch the stem, they either jump or fall off. They do not look like any pics of mealy bugs, leaf hoppers, or white flies that I have seen. And, they are killing off the stems of the clematis that they're on. They do not have any wings, and are a little smaller than a lady bug. Any ideas what it could be? Their shape reminds me of that volkswagon 'bug' car.

Thank you -I have been searching the internet for hours and nothing!

Alida