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Good to have nice images! You are dealing with phorid flies. These are commonly called humpbacked flies or scuttle flies because they have an arched back and tend to scoot rapidly back and forth. The larvae of these flies feed on decaying organic matter, especially material that has animal fats in it. We get infestations of these around restaurants where the grease trap isn’t being cleaned regularly or they are letting moist fats and oils accumulate under or around the kitchen. The flies will also breed in drains where food material and fats are entering. The best way to control this fly is through thorough cleaning and diligent sanitation.

In home situations, be sure to regularly clean your garbage cans (using plastic bags helps, but any goo that escapes into the can will serve as food for the maggots of this fly), be sure that your outside garbage is being regularly disposed of and the cans or dumpsters are being cleaned periodically. If possible, pull out the stove and check to ensure that no fats, oils and food waste has accumulated under or around it. Most refrigerators also have drip pans located in the bottoms. These should be checked and cleaned as they can accumulate dust and debris that is kept moist by the condensation. If you have floor drains (especially in the basement), pour a bucket of water through these on a monthly basis in order to eliminate any debris that may be accumulating in the traps. This can also serve as food for these flies. Be sure to check the outside of your home or building to see if there is any place that wet, decaying plant material is allowed to set! This fly can complete its life cycle in 15 to 20 days in warm weather. Homeowner compost piles that are kept too wet are a common problem!

There are several factsheets on this fly. I have attached a link below, but if it doesn’t work, just Google “phorid flies” and scroll down until you see the Colorado State or Clemson links.


Avatar_placeholder_01 David S.
Replied March 24, 2015, 12:06 PM EDT

Hello David,

Thanks a lot for your thorough answer. I will try to keep my trash out everyday. However, I don’t have animal fat in my kitchen. I barely cook meat here.

I am concerned because they disappeared for many months and then now, when it is getting warmer, they might be back. Is there any explanation for that? Is it possible they are coming in from a pipeline close to my window, as it was only when I left it open for a few days that I found them?

Does the fact that I found 3 dead ones, one big and 2 smaller ones, indicates they might have laid eggs in my kitchen?

Again, thanks a lot.

Anonymous Guest

Replied March 24, 2015, 12:38 PM EDT

Yes, with them being absent during the winter months, this would indicate that they are more likely breeding outside, but nearby. The larger one was likely female and the smaller ones were males. There is a considerable size difference between the sexes. If they were dead, this would also indicate that your dwelling is likely not a good place for them (too dry)…which would be a good thing! LOL!

I’m a little annoyed that your pest control professional didn’t know what these were! Area sprays and fogging is of little use against these flies as neither treatment will get to where the larvae are feeding. The flies are fairly common and we are getting increasing reports of them, especially in food handling facilities and hospitals! The last hospital I worked with that had an issue with these flies, the cause was traced to a broken sewer pipe that ran out of the basement! This was dumping “gunk” into the soil and the larvae were breeding in that! Not an easy fix, but when the pipe was fixed, no more flies!

Avatar_placeholder_01 David S.
Replied March 24, 2015, 12:52 PM EDT

Dear David,

Again, thanks!

So, besides cleaning my kitchen as good as I can and keeping my food in better containers, you would advice that I ask the super to check pipes in and around my apartment, as well as whatever is outside my apartment? I live in a building with many apartments, and so far according to him I’m the only who reported these bugs. I suspect that the communal trashcan might be problematic.

I was also annoyed with the pest control crew, because I clearly saw these were not fleas. Plus, they didn’t check on the plumbing nor asked if there was any organic matter outside. I figured out alone that my organic soil was being problematic, because I saw a couple of them in that part of my cabinet.

Should I be concerned of eggs given the recently found bugs?

Anonymous Guest

Replied March 24, 2015, 12:59 PM EDT

Ah ha! Yes, living in an apartment complex can be part of the issue as you have no control over what your neighbors do, nor how the garbage is handled outside your apartment! I suspect that there is something going on with the plumbing of the complex or how trash and garbage are handled, but getting the owner to do anything can be nearly impossible! Just keeping your place clean and using window screens when you have your window open will help keep the flies out. However, they are pretty small and any cracks or crevices in or around the screens can allow access to your apartment.

Avatar_placeholder_01 David S.
Replied March 24, 2015, 2:16 PM EDT

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Avatar_placeholder_01 David S.
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