1904-] 



The Sheep Nostril Fly. 



227 



Farmers are allowed to send cows to the bull at a fee of not 

 more than 10s. per cow, provided the list is not already full. 

 The total number of cows served must not be more than thirty 

 for six months. Each bull must be treated and kept in a 

 condition satisfactory to the authorities, who reserve the right 

 to inspect the animal at any time. No Government bull may 

 have access to cows suffering from any infectious disease, 

 especially pleuro-pneumonia and tuberculosis ; and no farmer 

 who has pleuro-pneumonia in his herd is permitted to send 

 cows within three months from the date of the last outbreak. 

 The bull is not to be allowed to run with cows, but it must be 

 kept in a special and well- fenced paddock. 



The Government stud bulls available for hire or for service 

 at the State farms in New South Wales are now thirty in 

 number, and they include animals of the following breeds : 

 Shorthorn, Jersey, Guernsey, Red Poll, Ayrshire, Kerry, Dexter- 

 Kerry, and Holstein. 



The Sheep Nostril Fly {Oestrus wis) belongs to the family 



Oestridae or Bot Flies. The mouth parts of the bot-flies are 



either abortive or rudimentary, so that as 



JP 1 ® Sheep adults they do not feed ; the harm is done 

 Nostril Fly. , , , 



by the larva or maggot which is parasitic on 



one of the higher vertebrates, the host — man, horse, ox, sheep, 

 deer — varying with the species of bot-fly. 



The sheep nostril fly has a wide distribution, and the harm 

 •done by its maggots is known to flock-masters in Britain from 

 north to south. 



The somewhat hairy fly (Figs. 1 and 2) measures about half an 

 inch in length ; the upper surface of the head is light brown, and 

 of the thorax light brown or yellow to grey with dark tubercles ; 

 the ringed abdomen is brown yellow with dark spots. The legs 

 are brown. The wings are glassy, and extend, when the insect 

 is at rest, beyond the body. The balancers (behind the flying- 

 pair of wings) are white, and are covered by well-marked 

 winglets, these winglets being present^ at the hind margin of 

 the flying wings. 



T 2 



