Unless you are trying to identify one of the larger and fancier moth species, moth identification is usually harder and less certain that butterfly identification. That's because there are more kinds of moth than butterflies, and many moth species are small, fairly unspectacular, brownish or grayish ones. You can see what I mean by taking a glance at our Moth Families Page. When you see all those names, remember that they are families, some of them with many genera, and many of those genera having many species!
Most field guides with moths in them are for "butterflies and moths," which means that butterflies are the main subject, but some of the more common moths are included. Moth fanciers in eastern North America are lucky that A Field Guide to Moths of Eastern North America exists.
Montana State University's Butterflies and Moths of North America Web site helps with identification by providing hundreds of thumbnail photos to choose from. If you can figure out what family your moth belongs to, go to the above site's Image Gallery, choose the family in the box, and scan the thumbnails of all the members of that family on file at the site.
You might practice this approach by identifying the moth at the left. Can you figure out its family? Once you know its family, can you find its thumbnail at the above site? With most web browsers you can see the moth's name by placing your cover over the image.
If you live on the the US eastern coast you may want to try this technique at the Moths of Maryland Website where you can also click on a family and see photos.
It's a great help in moth identification if you have a checklist of the species found in your area. Also, field guides with distribution maps for each species help the identification process enormously. If you are in Maine, for instance, you shouldn't have to try to distinguish your moth from a look-alike species in Louisiana.
Another approach, once you know the family, on your computer type the family's name into the box at the images" section of the Google search engine,. For example, if you think you have some kind of sphinx or hawk moth, you'd type in "sphingidae," since that's the technical name of the Sphinx Moth Family. Then you'll see hundreds of thumbnail pictures of various sphinx months at many websites all over the world, and maybe one of them will be the species you are trying to identify. If you see a picture looking like what you have, just go to the Web page where the image is found, and probably there you will find the moth's whole name.
Moths protect themselves from predators in some interesting ways. For example, can you figure out how the Polyphemus Moth, Antheraea polyphemus, illustrated at the left, might cause a hungry bird to go away? Notice how this moth's hindwings are adorned with what appears to be eyes glaring at us. Well, if you were a bird about to pounce on the poor Polyphemus, and the Polyphemus opened its wings and those big yellow eyes were suddenly staring at you, wouldn't you think twice about gobbling it up?
The moth at the left, with the curious name of "The Neighbor," Haploa contigua, isn't very colorful, but its bold wing patterns take advantage of a special camouflage technique known as disruptive patterning. In disruptive patterning, the outline of an animal is broken up or blurred, making it hard for a predator to know what it is seeing. Is "The Neighbor" one black and white insect, or six white insects on a black background? Or maybe it's not an insect at all. The moment of confusion disruptive patterning can bring about may be all the time an organism needs to escape being eaten!
Another way for a moth to confuse its predators is for its camouflage to blend it in with its environment. The Rustic Sphinx, Manduca rustica, at the right is clearly visible to us, but just imagine how hard it would be to see it if it were quietly perched on a brown tree trunk thickly covered with gray lichen! In the picture, notice the moth's long proboscis sticking into the flower's throat, being used like a straw to suck up the flower's sweet nectar. This species is found from the southern US south through Central America to Uruguay in South America.
The above Polyphemus Moth is a member of Giant Silk Moth Family, the Satrniidae, and that's a moth family you should know. This family is famous for its very large, showy moths -- with wingspreads up to about 6 inches across (15 cm). Caterpillars in this family often bear spines or tubercles, and are so large that their silken cocoons are sometimes confused with hummingbird nests. At the right you see such a cocoon "not much larger than an extra large chicken hen's egg," according to Maureen, who sent us the picture from West Palm Beach, Florida. The adult moth has already emerged from the cocoon, as you can see by the exit hole at the top of the cocoon, shown in the inset at the picture's lower right. I think this is the cocoon of a Polyphemus Moth.You may enjoy browsing Bill Oehlke's Large and Showy Moths (Saturniidae) of North America.
You may want to review some mothy books available at Amazon.com in the US, Canada and the UK by clicking here.