We just got home from a ten day vacation. We have been keeping a cocoon that we found a few weeks ago so the kids can watch it develop. When we got home there are these black small larvae of some kind in the jar. Do you know what they are? How did they get in there? We have very small holes in the jar and it is in our house. Thanks if you can help us
We believe these are Tachinid Fly Pupae. Tachinid Fly larvae are internal parasites on many kinds of insects and arthropods, and they are often species specific. Caterpillars are a favorite host. We are presuming the female fly laid her eggs inside the caterpillar before it formed a cocoon and the young flies fed on the internal organs.