banded tussock moth caterpillar

6150   I found this caterpillar in Weldon Park in London, Ontario a week ago (late September). Is it a banded tussock? I’m curious to know what the white things are on it’s back.  Kelly

This does appear to be a banded tussock moth caterpillar (Halysidota tessellaris; Lepidoptera: Lymantriidae). The white objects are the cocoons spun by larvae of a parasitic wasp (likely a braconid in the subfamily Microgastrinae) that developed within the body of the caterpillar. When the larvae are fully grown, they chew through the cuticle of the caterpillar and then spin a cocoon that protects them during their pupal stage. Ed Saugstad, retired entomologist; Sinks Grove, WV.