Found on the floor of the bushland – a leaf covered with large spheres.

I had the opportunity to go walking up the back in the bush yesterday. The sun reflected off an object laying on the ground which seemed vivid green.  Seeking this, I found a leaf covered with a cluster of large spherical attachments – too large for eggs, so presume they must be some kind of cocoon.  At first I thought they might be Gall Wasp cases, but in my experience, Gall Wasp cases are odd shapes, not uniform as these are. Gall Wasp casings also have a harder exterior, often with small holes.  The unidentified cases were smooth when I found them, slightly more wrinkled this morning. Picking up the leaf, it feels heavy, so I assume there is larvae still inside each one.

Can anyone tell me what they might be?  I’ve included a 5 cent coin in the photograph as a way of indicating scale.

As a comparison, this is what Gall Wasp casings look like.