Butterflies
No butterfly in North America can hurt you. Several are toxic to eat, which matters to a bird and not to you, and that toxicity is what makes this the group where lookalikes are the whole subject.
6 species, each checked against a reference source.
All species
Start with a photograph
Identify an insect from a photo. The result includes confidence, common lookalikes and a plain safety assessment; read its accuracy and limits before treating a low-evidence photo as definitive.
Butterfly or moth
The two are not separate branches of anything — butterflies sit inside the moths taxonomically — but the everyday distinction still holds up well enough to place what you saw.
- Antennae with a small club or knob at the tip: butterfly. Feathery or plain and tapering: moth.
- Rests with wings closed over the back: usually a butterfly. Flat or tented: usually a moth.
- Slender, smooth body: butterfly. Thick and furry: moth.
- Flying in full sun is a butterfly habit, though plenty of moths do it too.
- A chrysalis with no silk around it is a butterfly; a cocoon is spun, and mostly moths.
Here, looking alike is the point
More than any other group on this site, butterflies resemble each other on purpose. A monarch and a viceroy are separated by one black line across the hindwing veins. A female black swallowtail has evolved to look like a pipevine swallowtail, which is genuinely poisonous, and so have three or four other species. That means field marks here are small and specific rather than general impressions — and it also means the textbook version is often out of date. The viceroy was taught for decades as a harmless cheat riding on the monarch's reputation, and it turns out to be unpalatable in its own right.
Common questions
Do any butterflies bite or sting?
None. Adults feed through a coiled tube and have nothing to bite with. A few are toxic if eaten, which is a defence against birds, not a hazard to handling one.
How do I tell a monarch from a viceroy?
One black line crossing the veins of the hindwing. Viceroys have it, monarchs do not, and a viceroy is noticeably smaller.
What is the white butterfly in my garden?
Almost certainly a cabbage white. The white form of the female clouded sulphur accounts for most of the rest, and the underside hindwing spot separates them.
Should I raise caterpillars indoors?
For monarchs specifically, conservation guidance has moved against rearing in quantity — it spreads disease and appears to produce poorer migrants. Planting the right foodplant helps considerably more.