We were looking for viburnum leaf beetles on arrowwoods and found quite a few of these shapeless larvae. Could they be lacewing larvae? I don't see powerful jaws, but they have three pairs of very skinny legs and they are covered with waxy fuzz like some lacewing larvae. I hope that they are having a feast because, unfortunately, the VLB are everywhere on our poor viburnums destroying the tender leaves.
Almost four weeks later

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