136 



Oestrus ovLs caused great epidemics iu slieep in Russia in the 

 years 1848, 1849, 1854 and 1868. In recent years tlie disease has 

 spread considerably, especially in the northern districts of the 

 Governient of Taurida, where in some herds the number of infec- 

 ted sheep sulfering from fits in 1907 reached 10 per cent. The 

 obseryations of the author in some Governments of south and 

 south-east Russia (Bessarabia, Astrakhan) prove that these out- 

 breaks are in some places qiiite a normal state of things and that 

 in the spring or at the beg'iuning of summer, if the heads of sheep 

 Avhich have been killed be opened, larvae of Oestrusovisci\i\\x\\\Vi\s 

 be found. The author al-u gives some figures relating to othei" 

 countries. 



The last part of the paper is devoted to the question of remedies 

 against this pest. The author describes some of the older methods 

 that used to be in vogue, such as burning the steppes twice a year, 

 administering powders to the sheep to produce sneezing-, &c., and 

 explains their futility. Remedies intended to destroy the larvae 

 in the sinuses, such as injections of lime water, alcohol, dilute 

 naphtha, weak solutions of carbolic acid, &c., are also, in his 

 opinion, quite useless, only causing the larvae to creep deeper 

 into the different cavities. Surgical operations, such as tre- 

 panning, are also ineffective. In the opinion of Zurn, quoted by 

 the author, these operations and also the cutting away of the 

 horns, do not relieve the sheep. Zurn during the past year has 

 performed a great number of such operations and afterwards 

 injected different medicaments, but such good results as were 

 obtained were only temporary, and after a short time the illness 

 returned, sometimes with even greater force. One of the latest 

 remedies, used boih in England (Collinge) and America (Riley.. 

 Osborn), aims at keeping away the female insects by smearing 

 the nose and lips of the sheep with birch-tar, but in the opinion 

 of the author this method is also quite useless, as the insect will 

 always be able eventually to accomplish its aim ; and quite apart 

 from this, it never really touches the nostrils of the sheep when 

 depositing its larvae, but ejects a drop of liquid containing the 

 larvae into the nostrils as it flies rapidly past them. 



In the opinion of the author there is only one way of fighting" 

 this pest which is effective and at the same time quite simple. 

 Instead of fighting the larvae, all methods for which are either 

 quite useless or actually harmful, attention should be directed 

 towards the destruction of the adult insect. Purther it is only 

 necessary to capture those females which are on the wing during 

 the spring or summer, as the later generation will perish without 

 being able to deposit larvae. The metliod recommended by the 

 author can be best applied on the extensive open steppes, on 

 which in Russia sheep breeding is mostly practised, and is based 

 upon the characteristic habit of the insect of sitting motionless, 

 during tlie morning and evening or during bad Meather, on any 

 raised object, such as a wall or fence, that may be available. 

 If such a resting place is present, one can assume with certainty 

 that nearly every Oestrus ovis in the locality will visit it once 

 or several times during its life ; and if examined at suitable times 

 the insects can be caught with little difficulty. The author,. 



