© The Author, 2016. Journal compilation © Australian Museum, Sydney, 2016 
Records of the Australian Museum (2016) Vol. 68, issue number 1, pp. 1—22. 
ISSN 0067-1975 (print), ISSN 2201-4349 (online) 
http://dx.doi.Org/10.3853/j.2201-4349.68.2016.1657 
Revision of the Australian species of Hydropeza Sinclair 
(Diptera: Empididae: Ragadinae subfam. nov.) 
Bradley J. Sinclair 
Canadian National Collection of Insects and Canadian Food Inspection Agency, 
K.W. Neatby Bldg., C.E.F., 960 Carling Ave., Ottawa, ON, Canada K1A0C6, Canada 
bradley. sinclair@inspection. gc. ca 
Abstract. Nine new species of Hydropeza Sinclair from Australia are described ( H. angulata sp. nov. 
(N. Queensland), H. aptera sp. nov. (Tasmania), H. cornuta sp. nov. (Queensland), H. curvata sp. nov. 
(N. Queensland), H divaricata sp. nov. (N. Queensland), H. intricata sp. nov. (N. Queensland), H. 
queenslandensis sp. nov. (N. Queensland), H tasmanica sp. nov. (Tasmania), H. unguicula sp. nov. 
(Tasmania)). In Australia, Hydropeza is currently widely disjunct in distribution, known only from 
Tasmania and northern Queensland (Wet Tropics), absent from intervening regions despite extensive 
surveys of rocky streams and creeks. The male terminalia are illustrated, distributions mapped and a key 
to species is presented. The subfamily Ragadinae subfam. nov. is proposed for the Ragas -group of genera 
(Dipsomyia Bezzi, Hormopeza Zetterstedt, Hydropeza, Ragas Walker, Zanclotus Wilder). A revised 
phylogeny of the species of Hydropeza , including species from New Zealand and Chile, is presented 
and discussed. 
Keywords. Diptera; Empididae; Hydropeza ; new species; taxonomy; Australia 
Sinclair, Bradley J. 2016. Revision of the Australian species of Hydropeza Sinclair (Diptera: Empididae: 
Ragadinae). Records of the Australian Museum 68(1): 1-22. 
The genus Hydropeza Sinclair was erected for a New Zealand 
species described by Miller (1923), which was originally 
assigned to the Northern Hemisphere genus Trichopeza 
Rondani (Sinclair, 1999). There are ten New Zealand 
species and a single species described from Chile (Sinclair 
& McLellan, 2004; Sinclair & Plant, 2008). 
In Australia, Hydropeza was initially recognized from 
a large-sized undescribed Tasmanian species collected 
from streams and rivers (Fig. 5). More recently this genus 
was discovered from northern Queensland, where a series 
of new species are represented. The apparent rarity of the 
genus is in part likely due to the curious habit of the adults 
which fly rapidly about small cascades and pools with all 
six legs skimming on the water surface, making them hard 
to see especially in shaded streams and very difficult to 
capture with sweep nets. The author used small dip nets 
to collect individuals, which were virtually invisible at the 
base of small cascades. In addition, the use of lights set 
next to streams, Malaise traps set across streams, as well as 
pitfall traps and yellow pan traps have proven effective in 
capturing specimens. This paper reports on the Australian 
biotic diversity of Hydropeza for the first time. 
Hydropeza is assigned to the Ragas genus-group 
(Sinclair & Cumming, 2006), which is herein elevated to 
subfamily rank. The new subfamily is newly diagnosed 
and discussed. 
