Silk is made of proteins secreted in the fluid state by a caterpillar, popularly known as 'silkworm'. These silkworms feed on the selected food plants and spin cocoons as a 'protective shell' to perpetuate the life. Silkworm has four stages in its life cycle viz., egg, caterpillar, pupa and moth. Man interferes this life cycle at the cocoon stage to obtain the silk, a continuous filament of commercial importance, used in weaving of the dream fabric.

Natural Silk:  Natural Silk is insect fibre. It comes from the silkworm cocoon that the silkworm spins around itself to form its cocoon. A single filament from a cocoon can be as long as 1600 meters.

1. Mulberry Silk : The bulk of the commercial silk produced in the world comes from this variety and often silk generally refers to mulberry silk. Mulberry silk comes from the silkworm, Bombyx mori L. which solely feeds on the leaves of mulberry plant. 

 2. Wild/ Vanya Silk  : They are distinguish in looks and feel as they are procured from the wild silkworms that feed on leaves of castor, kesseru, payam, som, sualu,  oak, arjun, asan, sal etc… in the open jungles, imbibing the unevenness of nature, and reflecting it in the silks they produce They are distinguished in four different forms: muga, tropical tasar, oak tasar and eri.

 

Tantalizing Tasar:Tasar silk is produced by tasar silkworms (Antheraea mylitta and Antheraea proylei) that feed mainly on the leaves of Asan, Arjun and Oak. India is the second largest producer of tasar silk and the exclusive producer of Indian tasar

Magnificent Muga Silk: The pride of India, muga silk is known for its natural shimmering golden colour. traditions of the people of Assam. The vibrant Sualkuchi sarees aIts production is confined to Assam, border areas of neighboring Northeastern states and Cooch Bihar in West Bengal. It is produced by the muga silkworms (Antheraea assamensis), which feed on Som and Sualu. The most expensive of silks, muga is intrinsically woven into the culturalnd mekhla-chaddars are the traditional items made from muga silk. Use of muga yarn as a substitute for ‘zari’ in sarees is finding favour with reputed weavers

Irresistible Eri Silk :Eri silk, also known as the Endi or Errandi silk, is a creamy white-colored silk. It is derived from two domesticated species of silkworms known as Samia ricini and Philosamia ricin. Eri silk is a peace silk since it is spun from the cocoon of the silkworm without destroying the worm unlike mulberry and Tasar silk. Also known as Endi or Errandi, Eri is a multivoltine silk spun from open-ended cocoons, unlike other varieties of silk.

 

Reference : Wikipedia , Central Board of Silk