A term applied to the larvae of the three species of Mealworm Beetle. Adult beetles are about 15mm long, dark brown and scavenge in damp larders or down in basement food stores. They frequently breed in old birds’ nests. The larvae are large (up to 28mm) and pale yellow in colour, with clearly defined segments along the body. They are sold in many pet shops as food for fish and reptiles.
Rare in houses but, if you do find them, look for old birds’ nests, remove infested food, and dust or spray the area with an insecticide labelled for stored product insect or beetle control.