You will see the occasional Caddis pattern, usually a dry pattern vs. a diving caddis pattern (you can add an egg sac here too) with a colorful bump at the rear at the bend of the hook. This addition to the pattern is meant to represent an egg sac, which the female Caddis will be dropping, dabbing or diving to lay the eggs.

What color should the egg sac be? You see patterns with a hot red/orange spot as well as various shades of green, yellow to yellowish orange. The little bit of research I did, suggest the egg sacs for some Caddis is typically a shade of green to yellow. It might be worth a shot to add this touch to you Caddis patterns as you tie away this Winter for next year.

Ausable Queen by Tom Deschaine
Caddis With Green Egg Sac (musicarskikafe.blogspot)
Agent 99 Caddis, Thomas C. Duncan, Sr. (Danica)
Glow in The Ass Caddis, Casters FF

Hotter colors might be used, but I am not sure the pattern doesn’t then swing over into a attractor style vs. the theoretically more life like egg sac. Try them both.   Diving Caddis Patterns Without Egg Sacs…But They Could  Also, see this Mayfly version with an egg sac by Markov