Euchaetes egle, the Milkweed Tiger Moth, called the Milkweed Tussock Moth, eats both milkweed and dogbane. Both milkweed and dogbane are in the Apocynaceae family. (Dogbane is often mistaken for milkweed by people who raise Monarch caterpillars. Although their flowers and seed pods are not similar, their leaves are almost identical.)
Milkweed Tussock Moths lay their eggs in large clusters and sometimes cover their eggs with scales from their abdomens. Their egg clusters are often mistaken for spider egg sacs. Egg clusters, at other times, are laid without a scale covering.
Caterpillars are gregarious, staying closely together as they eat. Older caterpillars may separate a bit from each other on the plant.
Young caterpillars leave part of the leaf skeleton, a distinctive marker that this is/was the species that were eating the plant. Monarch and Queen caterpillars eat the entire leaf area or the entire leaf, not leaving a skeleton of the leaf behind.
Unlike Monarch or Queen caterpillars, the frass (excrement) of these younger moth caterpillars pile up on leaves in large amounts. Frass of Monarch and Queen caterpillars will be seen only in small amounts as the butterflies than use milkweed as a host plant are not gregarious but eat singly.
These yellow, black, and white caterpillars resemble a bit of tufted shag carpet. By the time they are finished, even allowing for predators, they often strip a milkweed plant of most or all of its leaves.
The adult moth has gray wings and a yellow/orange body with black dots down its back.