Ql 4 [November, 



concerning the sheep-mag-got flies of Australia. These are a number of species 

 of blow-flics and other Miiscoid Diptera which have acquired the habit of 

 laying their eggs, not niei-ely in wo\inds and sores — as sometimes happens to 

 domestic animals in other parts of the world — but on the siirface of "live" 

 wool (i.e., wool growing on healthy sheep), .when it is soiled with excrement, 

 etc., or even when it is only wet. The parts of the sheep attacked are generally 

 in the region of the anus, but if neglected the infestation spreads ; fresh flies 

 are attracted by the offensive smell of the damaged wool ; the maggots working 

 along the sheep's back cause masses of wool to slough off, leaving the skin 

 inflamed ; and if still neglected, the sheep finally dies, probably from some 

 form of blood-poisoning. 



Sheep-maggots seem to have been first observed in Britain, and the first 

 notice of them in print was in an old book published by William Ellis at 

 Dublin, in 1749. At the present day they are found all over the United 

 Kingdom, and in Scotland appear to have become a much more serious pest in 

 the last few years. They are recorded from Holland and France. A similar 

 kind of damage to wool has also been reported in recent years from New 

 Zealand, New Hebrides, Molokai (Hawaiian Islands) and South Africa. Thoiigh 

 it is not recorded from the East or from America, yet in parts of the latter 

 continent an allied form, the "screw worm" (Lucilia iJiaceWaria), sometimes 

 kills sheep, or even men, by entering the body through wounds, or even through 

 the skin. 



In Australia, where these insects are a most serioiis pest, the forms hitherto 

 identified in healthy wool are : four native species of Callipiiora and one of 

 NeocalUphora ; a native species of Lucilia and one of Sarcophaga ; the wide- 

 ranging Ophyra nigra ; and the following almost cosmopolitan species, all 

 common in Britain, and some of which may have been introdiiced into Australia 

 at an early date : Calliphora erythrocephala, Lucilia sericata and L. caesar, 

 Musca domestica and M. corvina, and Stomoxys ralcitrans. 



Sheep-maggot flies are recognised pests in all pai-ts of Australia, the 

 greatest damage cavised by them having occurred in Queensland and New South 

 Wales. But it is only about 18 years since they were first noticed attacking 

 healthy growing wool, though some of them may have infested Avoimds and 

 sores on the sheep at times much longer past. As stated above, several of the 

 species are peculiar to Australia, and have therefore been present all along, 

 while some of the imported species wei-e probably introduced at a much earlier 

 date than 18 years ago. Why, then, have such flies, noi-mally carrion-feeders or 

 saprophagous, recently acquired the habit of "blowing" live wool. ? Froggatt 

 considers that it probably first arose from their earlier habit of laying eggs or 

 living larvae (as the case may be) in the wool on carcases of sheep that have 

 died from drought. The similarity of the smell of soiled or damp wool on 

 living sheep to that of the dead wool might easily attract the flies to lay on the 

 live beasts ; while the decomposition set up by the first larvae would attract 

 flies of other species, and so on. Moreover, certain circumstances have caused a 

 vast increase in the number of the flies. For instance, at about the time when 

 this increase became very noticeal)le, war was being waged on the swarms of 



