124 



Froggatt (W. \V.) & Froggatt (J. L.). Sheep-Maggot Flies, No. 4, 

 — Dept. Agric. N.S.W., Sydney, Farmers' Bull. no. 122, December 

 1918, 24 pp., 4 figs. [Received 16th May 1919.] 



The work carried out at the Government sheep-fly experiment 

 station established near Moree, in the north-west, in 1917, is reported 

 upon. Studies on the question of the eradication of the sheep-fly, 

 Chrysomyia {CalUpJiora) rufifacies, have been continued for the last 

 four and a half years and all indicate that the main solution of the 

 problem lies in the destruction of its breeding-grounds. The blow- 

 flies that cause all the damage to wool and sheep have increased all 

 over Australia owing to the increase of suitable media, such as carcases 

 of dead animals. The obvious remedy for this is to render such material 

 unfit for further development of the maggots, and to hill all maggots and 

 flies on it. This can be done by poisoning it with arsenic water, by 

 burning and by screening [see this Review, Ser. B, v, p. 163]. Other 

 methods described for the destruction of the flies include the use of 

 traps for the adults, the most successful of which has been described 

 elsewhere [see this Review, Ser. B, vi, p. 74]. Several modifications 

 of this trap are described and their merits discussed. A hundred or 

 more of these traps should be used by each sheep-owner, and each one 

 can catch some hundreds of thousands of flies. Poisoning the bait 

 within the traps is considered unnecessary, as the flies caught can easily 

 be destroyed by passing a flare of burning paper over the gauze top. 

 Various baits for the traps were compared and tested ; a mixture of 

 fermented yeast and water gave very variable results, attracting 

 swarms of flies on some days and on others apparently proving no 

 attraction. Further tests with baits are in preparation. Spraying 

 sheep as a preventive against infestation has not given good results, 

 the sprayed sheep being no more immune from flies than the untreated 

 ones. Sheep that have been blown should have all infested or damaged 

 wool shorn off the skin, and then a dressing applied with a swab over 

 the infested area. Mixtures that have given good results in this 

 treatment include spirits of tar 1 pint, and kerosene about 5 pints ; 

 1| lb. sodium arsenite dissolved in 50 or more gals, water ; 1 pint 

 turpentine to 5 pints castor-oil, and bluestone solution. The last- 

 named is not recommended owing to its staining and hardening the 

 skin. The value of dipping and spraying [see this Review, Ser. B, v,' 

 p. 165] is doubtful, and in all cases the effects last only a short time. 



The breeding and distribution of the Chalcid, Nasonia brevicomis 

 on a large scale and the study of the other natural parasites proceeds 

 steadily [see this Review, Ser. B, vii, p. 100]. In response to requests 

 from many sheep- owners, simple instructions are given for the breeding 

 of N. brevicomis and its liberation. 



The season of 1918 was remarkable for the comparative absence of 

 blow-flies among sheep, and for the rapidity with which blown sheep 

 recovered. Flies responsible for the blowing of sheep during the year 

 and captured in traps included Pollenia {Calliphora) villosa (golden- 

 haired blow-fly), which was absent from October 1917 to April 1918, and 

 Anastellorhina augur {Calliphora oceaniae) (smaller yellow house 

 blow-fly), which disappeared in February and early March, Lueilia 

 sericata (English sheep-fly) was in evidence throughout the year. 

 Chrysomyia {Calliphora) ruffacies and C. varipes appeared in mid- 

 October and disappeared in early April. 



