William Morton Wheeler had this to say about swarming in Ants: Their Structure Development and Behavior (1910) page 183:
“When the hour for the nuptial flight grows near, a strange excitement pervades the ranks of the workers. At such times even the blind and etiolated workers of the hypogaeic species venture out into the sunlight and accompany the males and females to the entrance of the nest. The winged forms move about in tremulous indecision, but, finally venture forth, run about on the stones or climb about on the grass-blades till they have filled their tracheae with a plentiful supply of oxygen. Then they spread their wings and are soon lost to view high in the air.”