They are already in the bag.
This means, if they are unhatched, you eat weevil eggs. Oh yessss sirreee!
See below:
Q: Weevils - does anyone know how to get rid of them and stop them coming back please?
A: Success again - we have been contacted by Sandra Girard (a health inspector) who has advised as follows:-
"If you keep flour, cornmeal etc. in a cool place such as a refrigerator, the weevils will not hatch out. Also, if you have other products that already have weevils they will infest most grain products; flour, cornmeal, cereal, rice, spaghetti, etc. so throw these away immediately. When grocery shopping look for small holes in the packaging, web like substance, particularly in flour, or flying moths around shelves etc. This is a sign that there is a weevil infestation in the product.
The reason they recur is because the weevils are already in the product but do not hatch out until the temperature is optimum for them which is usually the Spring or Summer. The only solution is to keep the products cool so that the eggs that are already in the flour etc. do not hatch. By the way, these are microscopic and can't be seen until the insects hatch out.
It may be an idea to wash down shelves with a solution of bleach and water to sanitize the surface but this will not get rid of the insects." Ugh. Ugh!!!