My latest jag has been watching B Horror Movies on Netflix. I just watched Them! from 1954. It may have been a B Movie, but it scared the heck out of me when I was 6 years old.
Watching it now, I'm impressed by the acting and writing. The special effects were top-notch for the time, and it has a number of memorable performances, particularly by Sandy Descher who played the little girl walking in the desert at the beginning of the movie in shock. She left quite an impression on me and sold the whole story. Edmund Gwenn and Joan Weldon as the scientists still teach us a lot about ants. This was a leading role for James Arness and James Whitmore. The story is intelligently told, given its premise of giant mutants developing from radiation from the first atomic bomb tests in New Mexico. Fess Parker, Dub Taylor and Olin Howland, the alcoholic patient who provides the key clue to the presence of gigantic ants in the sewers of L.A. (ingenious plot line), singing "Make me a sergeant in charge of the booze!" all give stand out performances.
For quality and a good adventure, I give it 4 out of 5 stars.
The premise of ants being scaled up to the size of a cargo van poses a lot of logical problems, which is why the largest animal all have endoskeletons and/or dwell in water. There are limits to the weight that can be born by a chitinous exoskeleton and there would be difficulties relating to respiration and circulation which don't apply to most insects. Insects of this size are not feasible in Earth's gravity and atmosphere. But, hey, why let that ruin a ripping yarn?
Remember, keep your eyes on the skies and "Shoot the antennae!"