One of the problems encountered when trying to identify moths is the extreme variation that may exist within a species. I am not talking here about readily recognized "forms" but simply variation in coloration and markings. This problem is so common that any number of species might be used to illustrate it. The first case illustrated here is for the Velvetbean Caterpillar Moth, Anticarsia gemmatalis which is a very common species in the southern states that wanders northward in late summer.

A species introduced to North America, the wing spots usually give it away. So do the hindwings, but they may not be seen. The range of colors and extent of mottling is considerable. All these examples happen to come from Ontario. They vary in my yard, too.

The Arctiidae is a colorful family with many species that are difficult to discriminate. Numerous groups within the family have similar forewing patterns that vary remarkably. It is often necessary to get a good look at the hindwings, abdomen or forelegs to see markings that permit identification. In the Fall Webworm we might see specimens with immaculate forewings or ones that range from just barely dotted to very heavily patterned. Their larvae are also somewhat variably marked.