The wild silkworm Antheraea mylitta is grown and cultivated in several parts of India ranging from Bihar to West Bengal and several parts of Telangana. The wild silkworm rearing has been a source of income for the tribal populations who rely on it as income source; the intervention of government agencies has increased the cultivation. Our research involves understanding the secondary metabolites in the silkworm Cocoons and elucidating how the pupa survives the harsh environment during pupal diapause of the insect. We have realized the role of insect repellent compounds and other metabolites and their interaction with the insect. Wild silkworm Cocoons are the specialized natural structures constructed by Antheraea mylitta silkworms. They are the protein composites of sericin and fibroin as a structural material. The silkworm cocoons are presumed to be evolved structures through the course of evolution over millions of years. This chapter focuses on Biophysical analysis of chemical compounds, proteins and other secondary metabolites traced in the Wild Antheraea mylitta Tasar cocoons which are predicted to be the key factors to achieve the unique structural and chemical barriers to protect the pupa within the cocoons.