Gromphadorhina portentosa   Cool Cockroaches? The Madagascar hissing cockroach is wingless, slow moving, docile, has no odor, and does not bite. They can grow to be 2-3 inches long. Male roaches have two prominent protrusions on the thorax that look like horns. Females have a smoother thorax. Hissing is produced by expelling air from spiracles […]