BY ARTHUR WHITE. 67 



So far as I can uuderstand Macquart's descriptions of 

 Hirmoneura, nigriventris and H. punctata, these both refer to 

 varieties of the present species. Walker's Tricophthalma 

 guadricolor is also undoubtedly the same. The larger 

 males seem to be usually more or less orange in colour, the 

 smaller males generally drab, but connecting forms can be 

 found between them. At first I considered that these 

 represented distinct species, but after three years' careful 

 observation of the insects in their natural haunts, I have 

 come to the conclusion that all the varying forms belong to 

 only one species. The female seems to vary little in 

 appearance. 



The males of this species hover in the air, and dart rapidly 

 to and fro, in exactly the same way as the males of many 

 Syrphid^. The shrill humming sound made by the vibration 

 of their wings is very characteristic, and the insects may 

 usually be heard before they are seen. The females may be 

 found hovering in front of the blossoms of the flowering box, 

 or else settled on the foliage of young wattle trees. 



This species is confined to the bush ; it is widely dis- 

 tributed, and though pro^>ably somewhat local, yet seems to 

 be common where it occurs. It may be found on the wing 

 from the latter part of December to the middle of February. 



Family IV. CYRTIDiE. 



Bristleless flies of medium size, easily distinguished by their 

 extremely small head, inflated body, and very large squamae. 



Head very small, almost wholly occupied by the eyes, 

 which may be either bare or hairy, and which usually touch 

 in both sexes. Proboscis either long or rudimentary. 

 Antennse of widely differing forms and variously placed in 

 the different genera. Thorax very gibbous, the prothoracic 

 lobes sometimes enormously develojDed ; scutellum large. 

 Abdomen inflated and balloon-shaped, and more or less 

 pellucid. Legs simple, without any sign of bristles, although 

 the middle and posterior tibiae may be spurred. Wings with 

 a venation that varies very much in the different genera, 

 sometimes complicated and showing a connexion with the 

 Nemestrinidse, at others simple, with many of the veins 

 obsolete. 



The larvae of the Cyrtidce are parasitic on spiders. 



This family has not hitherto been recorded from Tasmania ; 

 it is however fairly represented, although all the species are 

 of very uncommon occurrence. Five species, belonging to 

 two genera are known at present, and it is probable that 

 other species remain to be discovered. 



