The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Examples from the Web for harvest bug
Yet the Acarus has eight legs, like a spider, and the harvest-bug six, like an insect.
While the harvest-bug makes us think of a spider, the body of the Acarus has a greater likeness to an insect's.