Polyphemus moths lay flat, light-brown eggs on a variety of leaves in trees such as birch, willow, oak, maple, and beech.

https://en.m.wikipedia.org/wiki/Antheraea_polyphemus#/media/File%3AAntheraea_polyphemus_eggs_sjh.JPG

 

Tiny yellow caterpillars will hatch about 10 tens after the eggs are laid. They will feed for 5-6 weeks on the host plant and can grow three to four inches in length and 3/4 inch in diameter.

https://en.m.wikipedia.org/wiki/Antheraea_polyphemus#/media/File:Antheraea_polyphemus_1st_instar_sjh.JPG

These caterpillars molt five times, the fifth stage being the pupa, before they turn into an adult.  In the firth stage or instar, caterpillars eat a tremendous amount.

https://en.wikipedia.org/wiki/Antheraea_polyphemus#/media/File:AntheraeaPolyphemusCaterpillar.jpg

 

Photo by Jessica Milne in Ontario

Cocoons are made out of brown silk, hence why they are called silk moths.   Once the adult moth hatches from their cocoon, they have to pump up their wings up with fluid.

https://www.publicdomainpictures.net/ro/view-image.php?image=294154&picture=polyphemus-moth-pe-teren

If the moth is a female, she will emit pheromones which the male moth can find with his large comb like antennae.  A male moth can fly for kilometers to find a female.

https://www.publicdomainpictures.net/ro/view-image.php?image=294154&picture=polyphemus-moth-pe-teren

Once the moths have mated, the female will spend most of her time laying eggs where as the male may go off and mate again.  Polyphemus moths have vestigial mouths, which mean their mouths have become smaller and they do not eat.  Adult polyphemus moths live less than one week before their live cycle ends.

 

Website information:

https://en.wikipedia.org/wiki/Antheraea_polyphemus 

http://butterflies.aa6g.org/Butterflies/Raised/polyphemus.html