To discover the girls marked with the maps, the Phynx must have sex with hundreds of girls. Their labors are lessened when in Rome they are given X-ray glasses, which visually strip the girls down to their underwear.
In order to find the girls marked by the maps, the Phynx had to engage in sexual encounters with numerous girls. The labors became easier for them in Rome when they were provided with X-ray glasses that revealed the girls' undergarments.