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Entomology (Study of Bugs)/Small Black Moth-like or slow-fly type bug


QUESTION: What is this small black-winged bug usually seen on walls or Window sills inside the home ???  Slow moving ...

ANSWER: Dear Vincent - I'm sorry, but I cannot provide you with an answer unless I can see an image of your mystery critter, and I do not see anything attached to your question.
Waiting to hear back,

---------- FOLLOW-UP ----------

QUESTION: Thanks... I determined it was a Drain fly.  It may be emanating from larvae unseen in a nearby stationary-tub drain or mudroom bathroom sink.
I am contemplating using enzymes to dissolve any residue harboring potential larvae.  One last possible source is a sump-pump room in the basement. However the drainage water is always very clear there.  I don't see where organic residue could accumulate to the extent it would provide an accommodating nursery like the other drains would.
The adult flies do smear when smashed & maintain a tiny dark triangular profile on walls & Window sills.
By the way, I'm in Southfield MI.

Dear Vincent - As long as you're certain they are drain flies (and from your description, those are the most likely suspects), you can find more control recommendations at and Additionally, your county office of he University of Michigan's Cooperative Extension Service can be of assistance when dealing with most pest problems - see for contact information.

Good luck, and hope this helps,

Entomology (Study of Bugs)

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Ed Saugstad


Will accept most questions in general entomology, including those related to medical entomology, taxonomy, ecology, arthropod surveillance, and pest management. If you are requesting a 'mystery bug' identification, PLEASE either attach an image to your question, or post an image on a web page (such as Flickr) so that I can look at it, as verbal descriptions frequently are insufficient for a definitive identification.


21 years in the U.S. Army as a medical entomologist; duties varied from surveillance of pest populations (including mosquitoes, cockroaches, ticks, and stored products pests) to conducting research on mosquito-virus ecological relationships and mosquito faunal studies. Ten years as a civilian analyst for the Department of Defense, primarily on distribution of vector-borne diseases worldwide. Limited experience on surveillance of agricultural insects in North Dakota and Indiana.

Entomological Society of America, West Virginia Entomological Society, Society for Vector Ecology, National Speleological Society, West Virginia Association for Cave Studies.

American Journal of Public Health, Contributions of the American Entomological Institute, Japanese Journal of Sanitary Zoology, Journal of Economic Entomology, Mosquito News, and Mosquito Systematics.

B.S. in entomology from North Dakota State University in 1963, M.S. in entomology from Purdue University in 1967.

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