Key to Families of Macromoths in California
David Hembry, University of California at Berkeley
Moths vs. butterflies
Moths vs. Butterflies
There are a number of simple ways to tell moths from butterflies. To begin with, butterflies fly during the day, and are usually more colorful than moths. This is not a foolproof way to distinguish the two groups, however, because many moths are quite colorful, particularly tiger moths (Arctiidae) and giant silkworm moths (Saturniidae). Furthermore, many different species of moths are active during the day. Many moths are much hairier than butterflies, but this is not true for all moths.
Ornate tiger moth (Apantesis ornata, Arctiidae)--very colorful, but still a moth.
Photo by TW Davies, California Academy of Sciences
A more reliable way to distinguish moths from butterflies is to look at their anatomical characteristics. To begin with, butterflies are capable of folding their wings together against each other and up over the back in a way that moths cannot. Moths must fold their wings rooflike over the body (so that the hind wings are not visible), or hold their wings out horizontally.
California sister butterfly (left); California oak moth (right; Phryganidia californica, Dioptidae). Note how the butterfly's wings are held erect up over the body, and the moth's wings are folded together rooflike over the body.
Left photo byTW Davies, California Academy of Sciences; right photo by Joyce Gross, UC Berkeley
Finally, the shapes of butterfly and moth antennae differ. Moths have variously shaped antennae (usually thread-like or feather-like). Butterflies have straight antennae with thickened knobs or clubs at the end, like in the picture below.
