FARM PESTS 27 



ground, there to develop in a week or so into the winged 

 insect. 



When sheep are restless and in poor condition, and 

 it is found to be due to nostril fly, the infected 

 animals should at once be isolated and prevented from 

 sneezing out the maggots on to pasture. In the case of a 

 valuable sheep, the nasal passage may be syringed 

 with salt water and permanganate of potash ; or 

 even the sinus cut into and the maggots removed. 

 Prevention is better than cure, however, and may be 

 accomplished by coating the sides of the salt troughs 

 with tar and fish oil, so that the sheep, in Hcking the 

 salt, get their noses smeared over with a substance 

 which will repel the attack of the Sheep's Nostril 

 Fly. (See Plate 5.) 



But we have not done with Diptera yet. We have had 

 Yellow-bottles, in the case of horses, and now come to 

 Green-bottles and Blue-bottles on sheep. These last 

 belong to the genus Muscidse, of which the common House 

 Fly is a conspicuous example. The Green-bottle {Lucilia 

 sericata) infests the skin and wool of sheep in the maggot 

 stage, causing irritation, much wagging of the tail, 

 inflammation and discharge from sores, with discoloration 

 and consequent loss of wool. The familiar Blue-bottle 

 (Calliphora vomitoria) also varies its usual diet of dead or 

 putrid meat to find board and lodging on sheep. The 

 maggots of these flies are famiHar to the angler as gentles, 

 wherewith to woo the unwary denizen of lake and stream. 

 L. Sericata, as its name suggests, is a shining green fly 

 and measures just over f inch across the wings. Like 

 all its kind, it breeds rapidly and continuously during 

 the warm months, sometimes accompHshing the complete 

 life-cycle within three weeks. The eggs are white and 

 tapering, about rV inch long. They are attached in 

 clusters of twenty to the wool and hatch within a day 

 in the height of summer. When full-grown, the maggot, 

 about I inch long, drops off to the ground and there 



