Female Egg-laying Caddis

I am re-reading Terry Hellekson's fine book "Fish Flies". In the book, Hellekson points out that the female caddis is often the most available to the trout as she lays her eggs on/in the water. He stresses the yellowish egg sack on the rear of the insect.

Using ice dubbing seems to closely imitate the egg sack. It almost looks alive if you look closely

I read the book quite a few years ago and had forgotten about his point. From now on, I will add an egg sack to my caddis flies as I want every advantage I can get on the water.

The bottom photo is a Miller Caddis with a small egg sack.