Thereva pygmaea Cole, 1923: 89 (preoccupied by Fallén, 1816: 234). HT male [USNM, catalog #25935]. Type locality: near Glen Martin, California (San Bernadino Mountains).
Thereva nana Cole, 1959: 148 (replacement name for Thereva pygmaea Cole; preoccupied by Fallén, 1816: 233).
Thereva nanella Cole, 1960: 118 (replacement name for Thereva nana Cole).