What insect has wings that look like flags?
Butterflies and moths have wings that resemble flags. They protrude from the body at a right angle and are shaped like long flags.
A flying bug with square flag-like wings is called a Common Whitetail Skimmer. It is a type of dragonfly. You may see them flying around lakes and ponds on hot summer days. Their wings aren't really shaped like flags, it's just that parts of their wings are so see-through, the colored parts sometimes look like flags on sticks from a distance.
I think the best way to put this is that their size depends on the size of the frog, but they are black or brown, smelly and contain indigestible insect parts, eg. moth wings, beetle shells, grasshopper legs. They look like little rocks but if you look at them closely you can tell that there frog droppings :)
They are actually quite different! An insects wings are a fixed shape and have an ecto-skeleton (like bones) in the outside and look very much like a leaf. Often there are two pairs together which can over-lap. A birds wing has the bones on the inside and they are hollow. The feathers spread open to increase the surface area and aid in giving "lift". There really aren't many similarities at all.