41 



THE BIONOMICS OF TAB AN US APREPES, AND OTHER 

 AUSTRALIAN TABANIDAE. 



By G. F. Hill, E.E.S., 



Entomologist, Australian Institute of Tropical Medicine, 

 TownsviUe, Queensland. 



(Plates I and II.) 



During recent years the number of described species of Australian Tabanidae, 

 or March-flies, as they are almost universally called in this country, has been in- 

 creased very considerably, and with this increase there has come a wider knowledge 

 of the distribution of the various genera and species. While advancement has taken 

 place in this direction, little progress appears to have been made towards acquiring 

 an accurate knowledge of the life-history and habits of any of these flies, and, up to 

 the present time, no precise information has been published concerning oviposition, 

 larval development, feeding habits and pupation of an}' of our numerous species. 



In this paper I propose to describe in some detail the life-history, habits and 

 developmental stages of Tahanus aprepes, Taylor, and T. rufinotatus, Bigot, which 

 have been reared from egg to adult, and to discuss other species so far as present 

 knowledge permits. 



Tabanus aprepes, Tayl. 



T. aprepes, Taylor, Proc. Linn. Soc. N.S.W. xliv, p. 56. 

 T. batchelori, Taylor, loc. cit. p. 58. 



Distribution. This species is recorded from South Queensland (Eidsvold), North 

 Queensland (Townsville and Kuranda), and the Northern Territor}- (Darwin and 

 Batchelor). 



Breeding-places. The following notes are based on observations made during the 

 period 18th October 1919 to September 1920, in three localities within the municipal 

 boundaries of Townsville, namely, (1) a small permanent rock-hole and stream arising 

 from it, situated within half a mile of the Institute building, (2) a small shallow 

 swamp about 250 yards distant from the rock-hole, and (3) a group of similar 

 swamps on the outskirts of the town. 



During the wet season and for some months afterwards the rock-hole and 

 adjoining pools and riffles (Plates I and II, fig. i.) are completely swept by a rapid 

 torrent of surface and soakage water from adjacent land ; but later, when the flow 

 is reduced to a regular and steady trickle, there is present a plentiful supply of algal 

 growth and three or four feet of clear water in the rock-hole and rather less in the 

 pools. From June to December 1919 the moist banks were searched unsuccessfully 

 for larvae and pupae resulting from eggs deposited during the previous summer. 

 On 10th October 1919 and later, Tabanidae were occasionally seen flying about, 

 or momentarily resting upon the heads of children playing on the sea beach distant 

 about 300 yards from the rock-hole — then the only locality within a mile or more 

 from which they could have emerged. The species could not be determined with 

 certainty, but was provisionally referred to T. aprepes. 



More frequent visits were now paid to the locality in the hope of definitely associat- 

 ing with it the flies occasionally noticed in the vicinity. Digging operations were 

 undertaken wherever the soil was sufficiently moist or loose enough to permit of the 

 emergence of the flies from the ground ; then the harder and drier parts of the bank 

 and neighbouring soil were dug over and sifted, the rocks and herbage overhanging 

 the water were searched frequentl}' for ovipositing females or their eggs, and a few 



