Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada

Nerax group

Robber Fly - Efferia aestuans Robber Fly - Efferia aestuans - female Robber Fly - Efferia aestuans - female Robber fly - Efferia aestuans Robber Fly ID Request - Efferia - Efferia Cape Cod robber fly - Efferia aestuans - male Robber fly (male) - Efferia aestuans - Efferia aestuans - male Efferia - Efferia aestuans - female
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Diptera (Flies)
No Taxon (Orthorrhapha)
Superfamily Asiloidea
Family Asilidae (Robber Flies)
Subfamily Asilinae
Genus Efferia
No Taxon Nerax group
Synonyms and other taxonomic changes
=Nerax Hull 1962
Numbers
13 spp. in our area, 65 total(1)
Identification
The following information is based on the modified Key to Eastern Species: (2) For info on the listed reference terms see the wing diagrams here.
1) - Furcation of third vein opposite or beyond base of second posterior cell;
18) - Posterior branch of third vein (R5) curved backward at tip, meeting the costa at or beyond apex of wing = (Nerax/aestuans group)

Examples:
Efferia aestuans
Efferia tabescens