Question
Hi there,
My friend has been having a fly problem for many years.  I haven't seen them but she said her exterminator said they are Green Bottle Flies.  But they behave like Cluster Flies.  Always come around mid to late summer.  She says they are in her bathroom and also by one window.  She keeps her place very clean but lives in a condo.  Everyone in her complex claims not to have this problem.  Is there someplace she can send one of these flies to have it analyzed so she can make an informed corse of action.

Answer
Hayley,

Cluster flies and green bottle flies are easy to tell apart. Green bottle flies have a metallic green abdomen and generally are not found indoors. Cluster flies have a patch of golden hairs behind the head (see http://www.livingwithbugs.com/cluster.html for a picture) and often occur indoors in late summer and early fall. Your description sounds like cluster flies.

The best place to take a specimen is your local county Extension office (www.extension.org).

Jack DeAngelis