Old black & white sci fi movie. On earth, time period in movie seemed 50's.
looking for name of TV Movie.
Showed thousands of human sized insect like creatures that could only be viewed through special lense device used by military that made it possible to see a fuzzy image of them when they existed in the past, swarming the area.
There was an additional scene while going downstairs into a buildings sublevel there is reference to how much time had gone by before the building they were in was actually built over the ruins of a very much older building. It was suggested that the old lines in the stone wall were very old and probably from the time of the area being destroyed by the swarm.