Entomology (Study of Bugs)/A cocoon? A nest?


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Hi Eric,

I've come across a few of these "cocoon-like" things on my walls (indoor) at home. They are all more or less the same size (oval-ish shape, smaller than the size of your pinky fingernail) and same colour (greyish). When i remove them from the walls, they are hollow (no insects living in them), dry with a crunchy texture.

Just wondering what this is, and also what type of insect could have potentially created this?

Many thanks!


I am not an expert on insects from Malaysia by any means, but your images remind me of something here in the states that we call the "household casebearer."  Here's more:


The cocoons shown in your images indicate that a full-grown moth has already emerged from the pupal case, since the pupal case (chrysalis) is empty in the images.

These are usually considered "nuisance" insects rather than certifiable pests.


Entomology (Study of Bugs)

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Eric R. Eaton


I answer insect and spider identification questions ONLY. Attach images if possible. No "what bit me?", "what do I feed this bug in captivity?", or science fair project questions please. NO TECHNICAL QUESTIONS ABOUT INSECT PHYSIOLOGY.


Principal author, Kaufman Field Guide to Insects of North America. Professional entomologist employed previously at University of Massachusetts, Chase Studio, Inc., and Cincinnati Zoo; contract work for West Virginia Department of Natural Resources, Smithsonian Institution, and Portland (Oregon) State University.

Author, Kaufman Field Guide to Insects of North America, Missouri Conservationist magazine, Ranger Rick, Birds & Blooms, Timeline (journal of the Ohio Historical Society). I have contributed to several books as well.

Oregon State University, undergraduate major in entomology, did not receive degree.

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One of the top 50 experts in all categories for AllExperts.com, 2009.

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Principal author of the Kaufman Field Guide to Insects of North America, Smithsonian Institution (contract), Cincinnati Zoo (employer), Portland State University (contract), Chase Studio, Inc (employer), Arkansas Museum of Discovery (guest speaker). Currently seeking speaking engagements, leadership roles at nature festivals, workshops, and ecotours.

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