Caterpillars in Your Yard and Garden - Page 5
Banded woollybear caterpillars (Pyrrharctia isabella) are present in the spring and from late summer to late fall. They produce one to two generations per year.
The banded woollybear caterpillar is often called the "weather worm" because in folklore the width of its black bands indicates the severity of the coming winter. Full-grown caterpillars are a little over 1 inch long and are covered with tubercles from which arise stiff hairs of about equal length. Middle segments of the abdomen are covered with red-orange hairs and the anterior and posterior ends with black hairs. Hair color and pattern (band width) are highly variable; often as the caterpillar matures, black hairs (especially at the posterior end) are replaced with orange hairs. Host plants are mainly weeds and other noncrop plants such as dandelion, dock, aster, goldenrod, plantain and some grasses.
About the family
Tiger moth caterpillars of the Arctiidae family, often called woollybears, are covered entirely with dense clusters of tubercles from which arise short tufts of hairs or long hair "pencils" of varying colors. The hairs on these caterpillars can be irritating when handled by individuals with sensitive skin.