Posted by Kahis on 29-09-2007 11:36
#20
I think they are inflatable sections of the pleural membrane. They can be found in several families, - but usually on females. At least in Lauxanidae, the surface of the sacks have very dense, specialised microsetae.
When a fly is dehydrated in acetone, these structures are often inflated and they stay visible on dired specimens.