In my state an Officer can only arrest on a misdemeanor charge if the crime is committed in his presence. (there are certain exceptions). With felonies an officer can arrest if he has probable cause to believe there was a crime committed and the suspect committed the crime. There are felony charges that are used to enable the arrest and proper identification of lawbreakers, but that they are never finally charged with.
ie. "Larceny from a Building" is always a felony, but the criminal is never charged with a felony unless the value exceeds a certain dollar amount or they have three or more convictions for what they are eventually charged with "Shoplifting"
Another example is "Defrauding an Innkeeper", again they end up being charged with simple larceny. The felony charge is used to enable the arrest and identification of the suspect. Once they are identified, fingerprinted and photographed they are released on bond and eventually charged with the misdemeanor.
The "felonies" are essentially practical administrative charges that allow the police to get involved.
