An egg sac made by an Black and Yellow Argiope spider. It is less than one inch
long. Spiders make 1-3 egg sacs per season. The egg sac is about three-quarters
inch long and changes color as it is made. The egg has two sections.  First the
spider makes the top section. To this it attaches the egg "mass"of several hundred
eggs . At this point  the overall shape is cylindrical. Then the spider spins web silk
over  both sections. In the process the initial "can like" shape turns into a tear drop
shape. Finally the spider adds brownish web silk as camouflage and tie-down silk
lines to reduce egg flutter caused by wind currents. These spider are known as
natures little builders. They are the most colorfull of the garden spiders. The
complete egg sac building process in shown in a companion DVD.

Nest   Spider Egg Mass

Additional material from source text for insert of The Big Egg Spider DVD.

The Big Egg Spider
A black and Yellow argiope spider is preparing to make a second egg sac. She
cleans the ends of her legs. An egg sac has a tear drop shape with top and bottom
parts of equal size. The top part attaches to several web anchor points and serves
as an attachment area for the bottom part. The spider starts with a full rounded
abdomen containing the egg mass and web material for the egg sac. When she has
completed ejecting the egg mass, her abdomen will be much flattened. She selects
a location near the main web and sets up a maze of criss-crossing web lines at
which the anchor points of the egg sac will be placed. She starts making the egg
sac, using a ribbon of web silk coming from her spinneret. In about six minutes
most of the top part is complete. The the egg sac resembles an upside down wine
glass, with it’s opening is across what is now the bottom. Next she places web silk
across the opening. The egg mass will be “pasted” to this web silk. The top half of
the egg sac is complete. Next she positions herself with her ovipositor pointing up
and centered under the closed-off egg sac. Then begins the ejection of the egg
mass through her ovipositor. The egg mass forms into a yellow ball between the
spider and the top part. At intervals while ejecting the egg mass, she pushes up on
the egg mass forcing it to adhere to the top part. After about five minutes the egg
mass is complete. The egg mass makes up the bottom half of the egg sac. The egg
sac has a cylindrical shape. A few seconds later she starts weaving web silk
covering the egg sac top to bottom. As several layers of web silk are added, the
shape changes from cylindrical to a tear drop shape. During this time the egg sac
also goes through several subtle color changes. The egg sac is complete and
contains hundreds of eggs. Next several “tie down” silk lines are added to the egg
sac. These lines attach from near the bottom of the egg sac to nearby points on the
web. The silk lines reduce egg sac movement that might result from wind blowing.
Next there is the “post partum” wandering. She wanders away from the egg sac
and returns. Repeating the action several times, each time ranging further away. A
short rest follows as she goes to a side on the main web and remains there for a few
minutes. Eventually she goes to the (back) underside center of the web. There she
waits for her next meal to be trapped on web the web.