THE BIONOMICS OF AUSTRALIAN TABANIDAE. 57 



various plants growing in a few feet of water at the margin of a small swamp (Locality 

 No. 3, Plate II) and removed to a concrete trough containing a pile of sand at one end 

 and water at the other. In this vessel they were fed upon molluscs until 3rd July, 

 after which date food was refused by them. The water was now drained off and the 

 sand allowed to dry gradually until only the bottom two inches remained moist, in 

 which condition it was kept for about four months. On 19th August one of the 

 larvae was found in a vertical position about three inches below the surface of the 

 sand. The body was then much contracted, but when placed on the surface 

 the insect became more or less active and extended its length to about 25 mm. 

 This specimen was allowed to bury itself again, and remained undisturbed in the 

 sand until 8th October, when it and two other larvae were found in the above 

 condition. One of these was preserved in the usual way and is described in these 

 notes ; the others were placed separately in live-inch fiower-pots full of sand and 

 imbedded in the sand contained in the larger vessel, where the two remaining larvae 

 of the original batch of five were presumed to be resting. The two larvae in pots 

 remained very active, but refused to eat either molluscs or earthworms, although they 

 came to the surface almost nightly until 18th November. On 26th November one of 

 these larvae was found undergoing metamorphosis, the other following on the morning 

 of 1st December (11 a.m.), the former producing a female fly on 12th December and 

 the latter a male on 17th December (between 9 and 10 a.m.). 



On 27th November the sand in the large trough was sifted and another larva 

 secured, which pupated on 12th December (5 p.m.) and produced a female flv on 28th 

 December. The fifth larva was not recovered and was, therefore, presumed to have 

 been destroyed by its fellows during the early days of their captivitv. From the fore- 

 going it will be seen that the pupal period in the laboratory was 16-17 days. Through- 

 out the greater part of their lives in captivity these larvae and pupae showed much 

 restlessness, and in the latter days of their pupal existence frequently wriggled to the 

 surface or projected the posterior end above it, proceedings which would have been 

 impossible under natural conditions owing to the hardness of the soil in which they 

 would have been embedded. 



As previously noted (under T. aprepes) a few larvae of this species were found in 

 the resting stage in a clayey bank in this locality on 25th April 1920, associated with 

 T. aprepes and T. riifinotatiis. On 15th June following five additional specimens of 

 T. nigritarsis were taken under similar conditions in the same locahtv. At the time 

 of writing (30th September 1920) the majority of these are still in the larval stage in 

 moist sand, others which at the time of capture were embedded in balls or tubes of 

 plastic clay and placed on the laboratory shelves to dry were equally healthy and 

 active when released on 30th September. 



The Larva. The adult larva measures about 35 mm. in length by 5-5 mm. in 

 width and is cream-coloured, faintly blotched and banded with yellow ochre (figs. 

 14-17). The pseudopods are arranged two on either side of the median line on the 

 ventral surface and one on each pleura, these and the dorsal tubercles being only 

 slightl}^ elevated. The surface of the cuticle is dull and distinctly marked with 

 longitudinal striae, except where banded or blotched. 



The Pupa. The pupa measures about 23 mm. in length by 4 mm. across the thorax 

 and 5 mm. across the abdomen at the widest part. The eyes are blackish brown, the 

 thorax slightly lighter and the abdomen argus-brown. The first abdominal segment 

 bears two slender hairs on either side of the median line, one on each pleuron behind 

 the spiracle, and two closeh' approximated hairs on the ventral surface near the margin 

 of the wing-sheaths. On the dorsal surface of the 2nd segment there is a double 

 row of bristles, the anterior row short, stout and of irregular size, the posterior much 

 longer ; the 3rd segment is similar to the 2nd ; on the 4th, 5th and 6th the bristles 

 increase in size gradually from the 4th posteriori}' ; on the 7th there are fewer long 

 bristles in the posterior row, their place being occupied by others of intermediate size. 



