I serendipitously discovered this little gem while checking out the online Field Guide to the Syrphidae of Ontario. Always looking for more caterpillar references, I went looking for a copy and found it for sale at Kettle Creek Conservation Authority. I paid US$12 with a credit card over the phone and it arrived today.

It's a small book but packed with lots of information. It aims to cover the easily identified caterpillars of Southern Ontario. With that in mind, you won't find any range information and the seasons are surely specific to that region. Nonetheless, I recognize most of the species from my own area here in Georgia, so it certainly has value as an identification aid.

There are good notes on identifying about 75 caterpillars, with some natural history as well. There are photos not just of the final instar caterpillars, but often of eggs, earlier instars, and the adult. There are even a few caterpillars pictured that I don't recall seeing in any of my other references.

Given the dearth of caterpillar references, I think this book is a good value, particularly if you happen to live near Southern Ontario.