The adult carpet beetle may be all black or may be grayish-brown with white spots. Adults are about one-eighth inch long. They are almost round in shape.
Carpet beetles can come into your house in several ways. Adults can fly in. You might bring them in on flowers or other plant material. Once in the house, the female may lay eggs on any food source, which will provide nutrition for her young. The larva feed on dead insects, dead animals or animal products, i.e., feathers, leather, furs, wool, silk, etc. They also like dried flowers, food crumbs, seeds, bone or blood meal fertilizer, and dried grain products (cracked wheat, oatmeal, cereals, noodles, etc.) From this list you can see that carpet beetle larva may be found almost anywhere in your house. The name carpet beetle comes from the fact that before nylon many carpets were made of wool, and these beetles were often found associated with damaged carpets.
The presence of the larva on your walls indicates that they are mature and are looking for a place to pupate. Many larva in one location indicates that they are leaving a nearby food source. An occasional individual probably came into the house on a bouquet or holiday wreath.
Check the area where the larva were found. Look for damaged fabric, contaminated foods, dust and debris associated with insect activity. Drawers or cupboards where the infestation is found should be thoroughly cleaned with a vacuum to remove all dust and debris which may be serving as a food source. Contaminated articles should be discarded or treated to kill any adults, pupa, larva or eggs. If the article is small, it can be placed in a bag and put in the freezer for several days. Clothing, rugs, etc., can be hung outside in the sun. Better yet, place the item in a clear plastic bag and place the bag in the sun for several days. Heat trapped in the bag will “solarize” the contents.