Preheat the oven to 375 degrees.
Cut the eggs in half lengthwise, remove the yolks and mash them.
Add mayonnaise, onion, seafood, salt and pepper to the yolks.
Mix well and pack into the egg whites.
Melt the butter and add the flour and curry powder.
Add the milk and cook, stirring, until the mixture boils.
Add salt and pepper to taste and more curry powder if desired.
Stand the eggs in a shallow baking dish and pour the sauce over them.
Sprinkle with the crumbs.
Bake until heated through and lightly browned.