These are common from mid-spring to fall just about everywhere I hike. They are nearly always spotted on milkweed plants. The bright color is advertising the fact they are poisonous if eaten due to feeding on milkweed.
Places I've seen them: Moose Hill in Sharon.
I see these first thing in spring, as soon as it starts warming up at all. They are tiny brilliant blue butterflies.
Places I've seen them: Moose Hill in Sharon, Broadmoor in Natick.
Commonly seen on sunny days from mid-June to fall. Very often seen around milkweed plants, which is both their juvenile food, and an adult food source.
Places I've seen them: Moose Hill in Sharon, Broadmoor in Natick, Elm Bank in Wellesley.
Colors seem to vary on these guys depending on what flower I find them in. They are almost always in a flower, and in my yard seem to prefer black eyed susans. They are freaking tiny though, maybe 1/2" across. Until I spotted my first one I had never had any idea they were so small, since all the pics I see of them are close-ups.
Places I've seen them: Moose Hill in Sharon.
Native to Europe these can be found in gardens in the North East United States. We seem to have a large number around my house.
Places I've seen them: My Back Yard.
I'll admit I don't know much about this one. I've only seen one and I almost walked into it on a trail. It dropped down to eye level, then crawled all the way back up to whatever tree it had come from.
Places I've seen them: Moose Hill in Sharon.
Look out on any plants overhanging the trail. Don't brush against anything without planning on checking for ticks when you get back to the car. These are slightly more common where dogs are walked, but not much more. They prefer cool damp conditions.
Places I've seen them: Everywhere, places dogs are allowed do seem to have more, as do damp dark areas Avoid long grass.
Bright metallic green bug I spot mostly on trails in deep forest. It is tiny and lands then flits away as soon as your camera is focused. Supposedly it can give a painful bite.
Places I've seen them: Moose Hill in Sharon, Wilson Mountain in Dedham.