There are at least 8 bands named Lethargy: 1) Smooth, technical death metal from Rochester, NY. Today Is the Day, Sulaco, Brutal Truth and Mastodon all feature alumni of Lethargy at some point. 2) Spanish electronic band with sensual female vocals. It was formed in Madrid in 1992 by Mayte Cruz and Julio Tomé.
"Hailing from Madrid, the duo Lethargy is described as a 21st century version of Massive Attack and Autechre, with a touch of Lassigue Bendthaus. A fresh mix of modern electronica with huge kicking beats and mesmerizing female vocals.

Read more about Lethargy on Last.fm.