D. hiemalis (Schött, 1893)

– Isotoma hiemalis Schött, 1893: 70

AK McAtee 1923; Folsom 1937 both as violacea var. mucronata; Christiansen & Bellinger 1980, 1998; Skidmore 1995

BC Fjellberg 2007

AB Fjellberg 2007

NF Arulnayagam 1995; Puvanendran et al. 1997

Remarks: The Alaskan record of this species is based on Folsom’s description of I. violacea var. mucronata, considered as a junior synonym (summer form) of D. hiemalis by Fjellberg (1976). Christiansen & Bellinger (1980, 1998) questioned the conspecificity of Nearctic and European forms. In fact Folsom’s specimens may belong to a number of other species, such as violacea (= inupikella) or alaskensis, which have been recorded in the same region. Nevertheless, Fjellberg (2007) recently confirmed the presence of true D. hiemalis in Canada.

General distribution: Holarctic, but most of the recent records are confined to Europe.