The story
Possibly a partial calque of translingual Armadillidium vulgare (literally “common little armadillo”).
Etymology from Wiktionary, CC BY-SA 4.0.
common pillbug
Today it means: A species of common terrestrial woodlouse, Armadillidium vulgare, native to Europe but introduced and widespread to North America; with a mostly-black exoskeletons and often with yellow patternage. Full definition →