I have 4 Garden spiders on webs attached to the back of my house.On one of the webs along with the spider there is this cacoon that's about 1 inch in diameter. What the heck is it? Is it full of baby spiders? Is it filled with food stored for later usage? Or something else>
This is a typical egg sac for this species (Argiope aurantia); the eggs hatch in the autumn, but the baby spiders remain dormant in the sac overwinter, emerging in the spring. See http://eol.org/pages/1194666/details for details.
