The thorax cover is Flexi Body. The best (most economical) way to prepare Flexi Body is to cut strips lengthways along the piece, with a craft knife and steel rule. Only cut through the Flexi Body, not the backing card. If, like me, you use a lot of Flexi Body you can prepare whole pieces this way and write the size of the strip on the back of the card.

(Please don’t use a scalpel for this. The blades are too flexible, they will wander as you cut. Not only is this dangerous to your fingers, but it spoils your Flexi Body as well).