A new project Caterpillars of Ontario and a companion guide were recently launched by @cmcheatle focused on Ontario lepidoptera.

This project aggregates butterfly and moth caterpillars with the goal of providing some assistance in IDing the species that we encounter in the province. Please have a look and feel free to add your own observations to the project. It is a work in progress as there are over 2,000 moths in the province, which makes the 180 or so butterflies easy to deal with. However, many of the moths are micros and/or have rarely seen caterpillars, so they are unlikely to show up in the guide soon.