Musca domestica or Sarcophagidae
The position in the first picture was a bit of a surprice. Lasted for app. 20 seconds, and after the reproduction session was over. They are not stuck in a web, they are standing on a web-nest from a type of moth.
Mixed meadow and woodland in the outskirts of a small town.
100 pathogens associated with the house fly may cause disease in humans and animals; pathogens are picked up by flies from garbage, sewage and other sources of filth, and transferred to human and animal food on fly mouthparts, other contaminated body parts, or through their vomitus/feces (http://bugguide.net)