Efferia-arida-group
Guides
Efferia coulei
Northwestern Hammertail
Efferia coulei is a robber fly (family Asilidae) described by Wilcox in 1966. It occurs in the grasslands of southern British Columbia, Canada, particularly the Okanagan Valley, where it is sympatric with its closest relative Efferia okanagana. The two species are genetically distinct, with approximately 7.0% divergence in cytochrome oxidase I (COI) DNA barcode sequences. As a member of the Efferia arida species group, it shares morphological affinities with E. arida and E. pinali.