We received a question from a reader a little while back about a worm she found in her sheets while using a lint roller. (To address the terminology issue up front, we should note that she probably found a larva in her sheets, not a worm, so we’ll use “larva” from here on out.) The reader shares her room with a cat, and although she doesn’t let the cat on her sheets for shedding-related reasons, she thinks the cat might be responsible for the larva’s presence in her room. If not, she suggests that it might be coming from her (the reader). In addition to the origin question, she also wants to know what the larva is, so we’ll address both of these matters below.