Cocoon shells were cut into cross-section slices by using a sharp blade for cross-sectional observation. Spines and hairs from G. postica and A. panda cocoons were collected using forceps. All samples were separately mounted onto copper stubs using double side sticking tape and were then sputter-coated with gold (JEOL JFC-1100E ion sputter) for three minutes to minimise charging under the electron beam. The samples were then studied with SEM (Jeol Neoscope, JCM-5000 (Nikon®, UK)) under an accelerating voltage of 10 kV with a beam current of 0.1 nA.