Persian melon by John Spottiswood.

These are large, round melons. They're excellent when vine-ripened, but mediocre when not. Avoid Persian melons that have green backgrounds below the netting--they were picked too early. Also avoid those with protruding stems, or tears in the rind at the stem end--it's a tell-tale sign that the melon was picked too soon. When ripe melons are picked, the stem falls off easily, leaving a small, clean depression. They peak in the summer months.