A reader sent us a good, if slightly disturbing, picture of a large group of white worms with black heads. The worms with black heads have congregated around an unidentified mass on the wall, which we presume is serving as some sort of food source. The wall on which the worms were found is in the family room of our reader’s home, and so not in the more common places one finds pest worms (like a pantry or toilet). The reader didn’t seem particularly alarmed by what she found, merely asking if we have “any ideas” about the small white worms with black heads. We’ll therefore approach this as a simple matter of worm identification and largely focus on this matter alone. What are the small white worms with black heads that our reader is finding?

First, take a look at the picture our reader sent in:

The image size is small, but you can still see that the reader is dealing with a fairly large swarm of worms, and all in a particular spot on the wall. It is harder to see exactly what these worms look like, but when you magnify the image, the worms are clearly white with distinct black heads. Magnifying the picture also reveals that the worms are feeding on something, although it is not clear what.

We have been using the word “worm” so far only to keep with the usage of our readers. In fact, she almost certainly found some sort of larvae, which aren’t worms, at least according to the definition of worm we adopt. As for what kind of larvae, a couple possibilities come to mind.

We actually wrote an article a while ago about white larvae with black heads that focused on what appears to be the exact creatures our reader is finding. In this previous article, we speculated that our reader found Indianmeal Moth larvae or moth fly larvae, two common household pests, and in the present case we won’t deviate from these suggestions (even though they are imperfect). Of the two, the creatures look more like Indianmeal Moth larvae; however, what complicates this hypothesis is that these larvae are almost always found in a pantry near certain types of food items – grains, cereals, pet food, and number of other dried goods – and for obvious reasons we don’t know how these items could be plastered on the wall in one’s living room. Moth fly larvae can also look like the creatures pictured above (although their bodies tend to slightly darker, and their heads aren’t necessarily dark relative to their bodies – they can be, though). The problem with this suggestion is similar to the problem with the Indianmeal Moth larvae suggestion: it is would be unusual to find a lot of moth fly larvae gathered on a wall in the living room. They tend to be found in highly moist places like toilets and shower drains, where they feed on decaying organic matter. So, both suggestions have their limitations, even though, based on morphology alone, these seem like promising suggestions. (If you are wondering why we didn’t suggest the larvae of houseflies, by far the most common type of flies, it is because their larvae, which are maggots, don’t have black heads.)

Although the reader didn’t request anything but an identification, we’ll briefly mention before concluding that she should get rid of the larvae by removing whatever is on her wall in the family room. (It is the mystery material on the wall, and as well as the fact that it is on a wall, that is our primary source of puzzlement.) Hopefully the problem is limited to this one area, and thus can be handled fairly easily. This advice applies regardless of what creature she is finding. Larvae gather in places with favorable living conditions, with their chief requirement being food. If you remove their food source, you essentially remove the larvae. (Of course, removing a food source can be difficult because it can require extensive cleaning in hard-to-reach places, but in our reader’s case, her cleaning task seems relatively simple and straightforward.)

Because so many larvae look the same, it is often hard to precisely identify what a reader found, and this is true in the present case as well. However, the the creatures look like Indianmeal Moth larvae or moth fly larvae, even if these suggestions are hard to square with their location in the reader’s house. In any case, she almost certainly found some sort of fly or moth larvae, and this is really the most relevant fact. A good portion of larvae infestations can be taken care of in the same way: with thorough cleaning.

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