Analyze the coloring of the larvae.
Brown eggs on window screen.
Come to think of it perhaps you ve seen these before.
The wasps fill nest cavities with grass and occasionally other plant fibers till the nest resembles a loose pile of brown grass clippings stuffed into a protected opening.
Maggots are completely white.
Do you keep a light on at night near this screen.
Well it s most likely that a moth has selected your window to lay her eggs.
For example if the color of the sac is pink or black then it is probably not a spider egg sac.
Some eggs sacs are brown yellow or even yellowish green.
However this is not true of all egg sacs.
In nature the nests are located in hollow stalks or stems of.
An unusual insect that few people get to see in iowa is the grass carrier wasp of the genus isodontia.
The name refers to the nesting habits of the female wasp.
These look like moth eggs and if you look carefully in the lower left corner there is a tiny recently hatched caterpillar we will attempt to identify the eggs but we are guessing a member of the family saturniidae or the subfamily arctiinae.
Observe the color to determine if what you are looking at might be a spider egg sac.
A thread in the insect and spider identification forum titled strange eggs laid on window screen.
Actually they look like patches of tiny little eggs hundreds of them.
You ve opened the curtains to take a look outside and you notice small light colored dots appearing on an area of a window or window screen.