32 Transactions. — Zoology. 



Key to the Genera. 



Fourth longitudinal vein forked . . . . . . . . Psilopus. 



Fourth longitudinal vein simple. 



Abdomen very short ; posterior cross-vein near margin 



of wing , . . . . . . . . . Liancalus. 



Abdomen large ; posterior cross-vein remote from the 



margin . . . . . . . . . . Ostenia. 



Genus Psilopus, Meigen (1824). 



Abdomen and legs slender ; face broad in both sexes, the 

 vertex concave. First joint of the antennae naked, the second 

 with bristles ; the third short, and with an apical or subapical 

 arista. Eyes generally hairy in the male. Fourth longi- 

 tudinal vein forked. 



In all the New Zealand species known to me the first 

 longitudinal vein hardly reaches the middle of the wing, and 

 the anterior branch of the fourth longitudinal emerges almost 

 at a right angle and then curves outwards, reaching the mar- 

 gin above the apex and near the tip of the third longitudinal. 

 The cilia on the squamae are pale. In the males the costa 

 has rather long bristles, which do not appear in the females. 

 There are black bristles on the second joint of the antennae, 

 the vertex, and the thorax. There are white hairs on the 

 face, behind the eyes, which are red, and not hairy. 



Key to the Species. 



Legs pale-yellow, the femora fuscous . . . . . . P. restrictus. 



Legs fuscous, the knees yellow . . . . P. mobilis. 



Legs black, the femora with green reflections. 



Arista dorsal . . . . . . . . P. malitiosus. 



Arista apical . . . . . . . . P. fuscatus. 



Legs pale-yellow, the tips fuscous . . . . . . P. gemmatus. 



Section A. Arista apical. 



Psilopus mobilis, sp. nov. 



Head and thorax bluish-green, with metallic reflections ; 

 abdomen bronzy, with dark bands. Antennae black, the arista 

 apical. Eyes red. Wings clear, the veins black. Legs 

 fuscous, the knees tawny, the femora with green metallic 

 reflections. Length, 5 mm. ; wing, 5 mm. 



Male. — Arista clubbed at the end. The anterior portion 

 of each abdominal segment dark-brown. 



Female. — The arista not clubbed at the end. The pos- 

 terior portions of the abdominal segments brown above. 



Hab. Christchurch (F. W. H.) ; Ashburton (Smith). 



Probably related to P. globifer (Wied). 



Peliopus fuscatus, sp. nov. 



Male. — Head and thorax metallic blue ; abdomen bronzy, 

 with dark bands. Arista not clubbed at the end. Wings 



