DIPTERA 



321 



This species lays from 300 to 600 eggs, but is not viviparous like 

 some of the indigenous blow-flies^. 



Pollenia villosa, Robineau-Desvoidy {Calliphora Icemica, Walker). 

 The Golden-haired Blow-Fly 



Probably introduced from Australia into the North Island, where 

 it became common before 1874. In that year it was first observed 

 in Christchurch. In 1900 it was first observed at Lake Wakatipu. 

 It is now abundant throughout New Zealand. Mr Hudson observed 

 it in Wellington in 1881. One of the most common meat flies in 

 houses. It deposits both eggs and maggots. In Australia it does 

 incalculable damage by blowing the wool of sheep, the maggots 

 burrowing into the skin of the animal, causing the wool to rot off. 



Although well-established throughout New Zealand, it has not 

 hitherto caused any appreciable damage among sheep. The cases of 

 sheep-blowing which occur in New Zealand are generally attributed 

 to Lucilia sericata, which is an erroneous idea, as any damage done 

 is caused by Pollenia villosa. 



Lucilia ccesar, Linn. Green-bottle Fly ; Sheep-maggot Fly 



First observed by Capt. Hutton in Christchurch in 1872; but it 

 was some years before it spread. It is particularly common in the 

 North Island and in Marlborough, where it causes fly-blow in sheep. 

 Dr Hilgendorf states that the eggs are laid on dogs, and the maggots 

 bore into the ham-muscles of living sheep. The species is not so 

 common in the South Island. Mr Philpott says : " during the summer, 

 odd specimens are often met with, and I once saw about a dozen 

 on a dead rabbit in March." 



^ Mr Philpott writes me as follows: "There is something peculiar about ovi- 

 depositing habits of the large blow -flies. In some localities it is quite unsafe to leave 

 blankets or any woollen fabrics uncovered, but in others they may be left exposed 

 from one year's end to another without being fly-blown. On the Tuatapere- 

 Preservation Inlet track a stock of blankets has been placed in each of the Govern- 

 ment huts, but it has been found necessary to provide zinc cases to keep them in. 

 These huts are all practically at sea-level, but the same trouble occurs at higher 

 elevations. The hut on the Hump is situated at about 3000 ft., but in hot weather 

 the flies are just as great a nuisance as down on the coast. In various parts of the 

 Wakatipu district campers are subjected to the same annoyance. On the other 

 hand, in a hut on the Hunter Mountains (at 3000 ft.) blankets have been left for 

 eight or nine years. They are never covered in any way, simply lie on the bunks, 

 or hang on the rafters, and no trouble from fly-blow has ever been experienced. 

 I have camped in this hut for four successive seasons, always in mid-summer; 

 the blue-bottles come into the hut freely and alight on the blankets,, but do no 

 harm. Last year I found that the furniture of the hut had been supplemented by 

 an uncured long-wooUed sheepskin, but even this failed to induce the flies to ovi- 

 posit. Also, I camped for a fortnight one year on Ben Lomond, at about 2000 ft. 

 This was late in November, and although the weather was hot, my blankets were 

 not interfered with. Unfortunately, I cannot speak with decision as to the species 

 of fly. It may be that the Hunter Mountain fly is Calliphora quadrimaculata." 



