MYIASIS— TYPES OF INJURY, LIFE HISTORY, HABITS 181 



plague of m^'iasis among sheep. The center of the region where this 

 scourge occurs is in New South Wales, where work for the commonwealth 

 government has been carried on by Professor W. W. Froggatt for several 

 years. Only a brief mention of the species concerned and the character 

 of attack can be given. 



The loss is brought about through the blowing of the soiled wool, 

 particularly around the vents of the ewes. The infestation, if not 

 promptly treated, spreads forward in the wool, resulting in a large loss in 

 the clip and often the larvae gain entrance to the bodies of sheep and 

 cause their death. Even though penetration does not occur, the skin is 

 acutely inflamed and gives rise to fever, loss of appetite, and sometimes 

 death. Froggatt states that he has bred 1,050 flies from the maggots in 

 one pound of wool. 



Froggatt holds that the blowing of wool is largely an acquired habit 

 on the part of Australian flies, as practically no cases of this kind we7"e 

 noted up to 1903 or 190-1. He attributes the acquisition of this habit to 

 the extended drought which destroyed large numbers of animals of all 

 kinds and resulted in the production of myriads of flies. He thinks that 

 during this period several species of flies acquired the habit of depositing 

 in "smelly" wool. He also considers the more extensive breeding of heavy 

 wooled sheep to be a contributory factor. It is certain that injur^^ from 

 blow-flies has developed from an almost unnoticed trouble to a problem 

 of first magnitude within the space of a few years. During the first 

 few 3'ears of the acute trouble the small yellow house fly, Anastellorhina 

 augur Linnaeus, and the golden hair blow-fly, NeopoUenia stygia 

 (Fabricius) Townsend (Pollenia villosa Robineau-Desvoidy) appeared 

 to be the principal culprits. In 1913, when the work was taken up more 

 extensively it was found that the "green and blue" sheep maggot fly, 

 Chrysomya rufifacies Macquart (Pycnosoma), was assuming first impor- 

 tance in connection with the infestation of sheep. The difference in 

 apparent injuriousness is probably governed largely by the seasonal 

 conditions as in the case of species in our own country, C. rufifacies appar- 

 ently being concerned largely with cases of myiasis in summer and A. 

 augur during the cool weather. The life histories of these flies do not 

 differ materially fi'om that of the screw- wo rai fly, the life cycle being 

 completed in about tw'o weeks under favorable conditions. Other species 

 which have been bred from wool in Australia are Microcalliphora varipes 

 (Macquart) Townsend, the Anthomyid, Ophyra nigra Wiedemann, 

 Sarcophaga aurifrons Macquart, and the cosmopolitan Lucilia sericata 

 and L. casar, and possibly L. tasmaniensis. 



