You are here:

Entomology (Study of Bugs)/Small Black Bug in Window Sill


Close-up Photo
Close-up Photo  

Another Picture
Another Picture  
I have been mystified by the appearance of these tiny black bugs which have appeared on my window screens and dozens have collected on the window sill between the window and screen. I keep the windows closed so they do not come in my home. They are tiny, perhaps 1mm in size. I have attached a close-up photo of one on my window screen and as you can see from the photo it can easily fit through the small openings in the screen. They do not move very often and when they do move they either jump or fly, it is hard to tell as they are so small.  When looking at them with the naked eye they look like a small black speck. I live in a two story home and they are mainly located on the second floor windows. Also, they appear in the spring and disappear in the winter, I live in Indianapolis.
Any help with identifying these little guys would be greatly appreciated!



Nice image of a dark-winged fungus gnat, family Sciaridae.  I'd love if you'd share the image with me so I could use it in a blog post about these insects.  I would need your full name for credit, a date, and geographic location in the e-mail with the image file...

Here is more about the gnats.  They feed as larvae on decaying organic matter, and are frequently abundant in the potting soil of overwatered houseplants.

Hope the above helps.  In my experience they are at worst a nuisance, and the adult flies live only two- three days, dying in the soap dish.


Entomology (Study of Bugs)

All Answers

Answers by Expert:

Ask Experts


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.

Awards and Honors
One of the top 50 experts in all categories for, 2009.

Past/Present Clients
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.

©2016 All rights reserved.