Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Class: Dicondylia
Subclass: Pterygota
Order: Ephemeroptera
Suborder: Furcatergalia
Infraorder: Scapphodonta
Superfamily: Ephemeroidea
Family: Ephemeridae
Subfamily: Icthybotinae
Genus: Icthybotus
Species:  Icthybotus hudsoni and Icthybotus bicolor

Mayflies in the genus: Icthybotus are endemic to New Zealand. Icthybotus in the genus of Ephemeridae and is represented by 2 described species, Icthybotus hudsoni and Icthybotus bicolor. 
Their larvae have 6 pairs of bifid (split into two parts), plumose gills held over the abdomen. Their mandibles are tusk-like and extending well in front of the head. 

Mayfly nymph Genus Icthybotus.jpg  

Dorsal view
Icthybotus mayfly nymph.jpg 

Icthybotus hudsoni a burrowing mayfly nymph.
Icthybotus hudsoni Burrowing Mayfly-002.jpg

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/