1900] 



89 



SHEEP. 



Maggot of Sheep's Nostril Ply. CEstrus ovis, Linn. 



CEsTKUS OVIS. — Fly, magnified, Hue showing natural length ; maggot ; mouth 

 hooks of maggot ; and tail segment, showing spiracles, and lobes, acting as organs 

 of progression — all magnified. After Brauer. 



The attack of the Sheep's Nostril Fly is becoming much better 

 understood than it was formerly, both with regard to its life-history 

 and as to methods of prevention ; but still, from enquiries sent, the 

 infestation is evidently not as well known as is desirable. In itself it 

 may be easily recognized, and preventive measures may also be easily 

 applied, but complications arise from it being sometimes confused with 

 the brain disease known as the " Gid," or staggers, which arises from 

 quite a different cause ; sometimes also observation of a chance pre- 

 sence of the maggots, when they have from some special circumstances 

 strayed down into the throat, leads to enquiry as to what the attack 

 can be. 



I have never had many enquiries about it in any one year, but 

 for more than fourteen years information has been asked from time 

 to time, and last season the following enquiry was sent me, with 

 specimens accompanying, on June 27th, from near Horncastle, in 

 Lincolnshire * : — 



" The enclosed grubs were taken out of a Sheep's head at the top 

 of the nostrils, as near the brain as we imagine they could get ; six in 

 number ; when taken out, all alive. The Sheep's head was purchased 

 from a local butcher, so I am not able to say anything about the 

 appearance of the Sheep. I shall be much obliged if you will give me 

 your advice, and what they are, and what damage they do to the 

 Sheep if not disturbed, and where and how they get worked up the 

 nostrils." 



The specimens sent showed the attack to be of Sheep's Nostril 

 Maggot. When full-grown these grubs are about an inch in length, 

 and about a third of an inch in width, but, from their powers of 



* I do not give my correspondent's name, as this is not always wished. 



