The male, female, and larva of Micrasema florida, n. sp. (Trichoptera: Brachycentridae), is described from Coastal Plain streams of Alabama and the western Florida panhandle. The species belongs in the Micrasema rusticum Group and closely resembles Micrasema ozarkana Ross and Unzicker, 1965. The male lacks thick, sclerotized straps on abdominal segment IX. The female has anterior emarginations on the abdominal terga. The larva has a pale yellow head with light brown muscle scars and builds a case that is abruptly narrowed posteriorly.