1) the larval form of the antlion (also spelled ant lion), also known as a backward bug or backwards bug. It is a true insect.
2) the pill bug (a crustacean, not an insect- Order: Isopoda). Its various species are found all over the world. English slang names include: roly poly (spelled many ways), doodlebug, woodlouse, woodbug, armadillo bug, ball bug, bowling ball bug, hardy back, potato bug, slater, chuggy pig, butcher boy, carpenter, cheesybug, cheeselog, daddy gamfer (also spelled daddy gampfer), beetle bug, and Granny Grey. The most common slang names in America are roly poly and doodlebug.
3) the sow bug (also a crustacean in the Order Isopoda), which looks much like the pillbug, except it can't roll up. It has some of the same slang names as the pill bug.
1) The child dropped an ant into the doodlebug's pit, and watched in facination as the sand monster grabbed it.
2) The doodlebugs rolled up into tiny balls each time the children flicked them with their fingers.
3) Maxie caught a doodlebug that couldn't roll up.