Quote from [link]
Structurally, Cyclosa spiders can be easily recognised by the characteristic U-shaped demarcation between the raised "head" (the cephalic part of the cephalothorax) and the flat thoracic region. The egg-sac is yellowish brown and woolly in appearance.
Spiders of the genus Cyclosa decorate their vertical orb-webs with a band of rubbish made of remains of insects bound in silk. The spider sits in the hub and appears to be a part of the debris, thereby camouflaging itself. The vertical orb-web is decorated by a vertical band of debris through the centre.