INSECT ENEMIES OF LIVE STOCK 183 



greasy or soiled fleeces. Lambs, or enfeebled, old, or 

 unhealthy sheep are usually chosen for attack. The larvae 

 bear a considerable superficial resemblance to those of 

 the house fly; they are pointed at the anterior or head 

 end, and broad at the hinder end, where the spiracles are 

 situated. They are provided with somewhat formidable 

 mouth hooks, with which to tear the flesh of their hosts. 

 In a fortnight the maggots, being full grown and about 

 half an inch in length, change into brown, barrel-shaped 

 pupse, so common amongst dipterous insects. As the life- 

 cycle is rapidly completed, several broods may occur in one 

 season, and, as sheep once attacked are more liable to future 

 infestation, it follows that considerable harm may be and 

 often is done by these flies. 



The sheep maggot flies are, at the present time, the 

 greatest menace to the sheep-raising and wool industry of 

 Australia. The European green-bottle fly, though by no 

 means a recent importation, has, till recently, confined its 

 attentions to dead meat, but now is making its presence felt 

 in no uncertain manner. Two blow flies, Calliphora oceanice 

 and Calliphora villosa, have, in the past, done considerable 

 damage, but are being rapidly superseded by the metallic 

 blue blow fly, Calliphora rufifacies, which affords an 

 excellent example of a fly, once harmless, taking to evil 

 habits. In 1912, damage, estimated at a million sterling, 

 was done by these flies alone in New South Wales, and as 

 much again in Queensland. The situation became so serious 

 that a sheep maggot-fly experiment station was founded, 

 with the object of working out the life-histories of the 

 insects, and, if possible, of finding a means of eradication. 



Calliphora rufifacies, which has long been known to 

 the squatters as the hairy maggot fly, is about one-third 

 of an inch in length, and of a general, deep metallic blue 

 colour, sometimes shading into green on the abdomen ; the 

 legs are black, the wings transparent, and the veins black. 

 The space between the eyes is black, with the rest of the 



