In 1975 and 1976 an outbreak of the saddled prominent caterpillar, Heterocarnpa guttivitta (Walker) was observed in Beech-Maple climax forests on Beaver Island, Michigan. The adult guttivitta moths emerge in late May and early June, mate, and lay small (1 mm) eggs on the underside of leaves. One female lays about 500 of the green spheres. In 9-10 days the eggs hatch, and the larvae go through characteristic changes in form and markings through the following five instars (Allen, 1972).
Loesch, Alice and Foran, Jeffry
"An Outbreak of the Saddled Prominent Caterpillar, Heteocampa Guttivitta (Lepidoptera: Notodontidae) on Beaver Island, Michigan,"
The Great Lakes Entomologist, vol 12
Available at: https://scholar.valpo.edu/tgle/vol12/iss1/8