Accidental science experiment

We have an accidental science experiment going on at our house. My grandma sent some leafy vegetables from her garden and had them in a bag. When my mom open the bag there were caterpillars inside. She got rid of the vegetsbles and emptied the bag outside. Some of the Catapillar's must have released from the bag and now there are butterflies that we keep finding flying around our house. It was kind of cool at first but now we don't want to keep finding them inside the house. We try to catch them and let them go outside. All of the butterflies are yellow with a pattern on them. I am glad they are butterflies and not something more gross.