Key to the genera of New Zealand Syrphidae

1. Postpronotum bare; head posteriorly strongly concave and closely appressed to thorax so that postprono- tum is partly or entirely hidden (Fig. 18); male abdomen with tergum 5 visible dorsally ( SYRPHINAE)9

- Postpronotum pilose; head posteriorly less strongly concave so that postpronotum is clearly exposed (Fig. 19); male abdomen with tergum 5 not visible dorsally ( ERISTALINAE)..................................................2

2. Anterior anepisternum pilose.......................................................................................................................6

- Anterior anepisternum bare.........................................................................................................................3

3. Cell R2+3 closed (Fig. 10).............................................................................................................................8

- Cell R2+3 open (Figs. 11–16)........................................................................................................................4

4. Face with a tubercle; vein R4+5 strongly to moderately sinuate; metafemur with basolateral patch of black setulae, without a ventroapical tubercle or carina ..................................................... Helophilus 12 (7) spp.

- Face without a tubercle (Fig. 24); vein R4+5 straight or only slightly sinuate (Fig. 11); metafemur without patch of setulae, with ventroapical carina or tubercle.................................................................................5

5. Wing completely microtrichose; metafemur with a ventroapical tubercle; metepisternum bare .................. ......................................................................................................... Paratropidia 1 sp.; bilineata (Walker)