I live in Southern California and I noticed these little nests in 2 corners of the house and on the back of a outdoor patio furniture cushion. They are hard but when I hit it, it falls appart like dried mud. I took some pictures after opening (my wife didnt know what it was and poke at it with a broom). Anything to worry about? Should I call a exterminator? It is maybe 2 inches wide.
Mud dauber?
Mud dauber (wasps in the family Sphecidae) can take many forms - see http://tinyurl.com/2ahnqay for some examples. These strictly are surface structures, and do not 'penetrate' anything. The wasps themselves are not aggressive, and will sting only if severely provoked (see http://tinyurl.com/2bo52xd).
Thank you all for the help. I have brushed it away and no holes and all gone. ^
