Eggs hatch in one to three weeks. The larval stage of the furniture carpet beetle is responsible for causing damage. The larva is 5 mm long, oval, and covered with brown hair. The larva of the common carpet beetle, Anthrenus scrophulariae , is difficult to distinguish from that of the furniture carpet beetle. One way to distinguish the furniture carpet beetle from the common carpet beetle is to look for the presence of a long pencil of hairs at the end of the body that continually vibrates which is indicative of the furniture carpet beetle.
Larval color is dependent on the color of the food substrate.
The number of larval instars may vary from six to 12 and requires two to three months before pupation occurs. The larvae of the furniture carpet beetle pupate in their last larval skin and are white in color. Pupation occurs on or near the larval food source. The pupal stage lasts an average of two to three weeks depending on temperature. Color patterns vary but the adults can be distinguished from other species of carpet beetles by examining the body scales with a hand lens.