Usually called 'window screen' in American English or just 'screen' if the context is clear. I doubt 'mosquito screen' would be unclear to any English speaker

Usually called 'window screen' in American English or just 'screen' if the context is clear. I doubt 'mosquito screen' would be unclear to any English speaker so it's fine to say. If a screen is on a door you call it a 'screen door' if you have a full enclosurer to protect you from bugs it's a 'screen house.'