Plot hole: After less than 1 minute of investigation Scully found out that the photograph was bogus. It tells a lot about the "very best" specialists, mentioned by the Deep Throat later on, who had prepared the photo. (00:19:10)
Plot hole: The bugs are related to a type of mite, and when they are shown under a microscope they look like a glowing lice without wings. The problem is they are swarming in the air so they have to be able to fly - no way to do that without wings.
Answer: He was being facetious. He doesn't specifically know that information, he was merely giving examples of the types of information he has access to.
I think so too.
lionhead