96 ENTOMOLOGICAL SOCIETY OF ONTARIO. 



METHODS OF ATTACKING PARASITES OF DOMESTIC ANIMALS. 

 By Herbert Osborn, Ames, Iowa. 



In dealing with insect parasites of domestic animals we need to consider, first, the 

 method of attack of these parasites, and we may conveniently separate them into the 

 external parasites and the internal parasites. Among the former we have various species 

 of lice, itch-mites, ticks, and can also include those forms which affect the external parts 

 of the body by depositing eggs in sores. In the latter series we may include the dif- 

 ferent kinds of bot flies affecting ths internal organs and certain forms of degraded 

 Acarina which also afiect certain internal organs. It is unnecessary here to detail the 

 mode of attack of the external forms more than to mention that some pierce the skin to 

 suck the blood, others simply feed upon external excretions, producing pustules, scabs, 

 etc. 



First among the methods of treatment we should consider that of prevention, since, 

 for perhaps the majoiity of the parasitic forms, a little effort in the direction of preven- 

 tion is far more eSective than costly and laborious methods later on. 



With a large majority of parasitic species, including all of the lice, the sheep-infest- 

 ing Hippoboscidse and all of the Saicoptida?, infection results from the mingling of 

 parasitized animals with those which are free from parasites. It is therefore possible by 

 attention to animals introduced into a herd, or sometimes into a new section of country, 

 to prevent entirely the introduction of the parasites. To accomplish this it is necessary 

 to examine introduced animals, and if infested, or suspected of being infested, use 

 thorough treatment upon these. In the case of introduced cattle infested with Hypo- 

 derma it would seem possible that they might, by being carefully watched and the grubs 

 destroyed, be prevented from introducing this pest in any new locality. Since the 

 parasite occurs only in the bodies of cattle during the winter season, I see no reason why 

 attention to imported cattle should not serve to totally exclude this pest from any locality 

 which has hitherto been free from it. The bots in horses may be prevented by the well- 

 known method of shaving off the eggs, so as to prevent the introduction of the lai-vas into 

 the mouths, while for the bot fly affecting the sheep T am not aware of any more effective 

 plan of prevention than that of applying tar to the noses of the sheep. For direct treat- 

 ment, the methods for external parasites may be grouped under the bead of washes, 

 powders, and fumigation. The use of washes, in the treatment of paiasites is perhaps 

 one of the oldest methods. The modifications consist in the methods of applying or in 

 the materials used as a wash. The method of application will depend somewhat upon 

 circumstances, but should aim to reach all parts of the body, and particularly those parts 

 most infested. Sponging the animal with a cloth or sponge dipped in the insecticide 

 material and application by means of force puuip in certain cases, pirticularly for hogs 

 and thin-haired animals, is practicable in certain forms. A device recently presented by 

 Dr. Francis, of Texas, provides for the pressure by means of gravity, the barrel being 

 elevated on a derrick and connected by hose with several nozzles directed downward, and 

 a movable one to use in spraying the under parts of the body, the liquid being collected 

 by a drip platform in a receptacle below. The liquid, however, is elevated by a pump, 

 and while it may lessen the number of men necessary in spraying, the same end can 

 easily be accomplished where a force pump is at hand, if it is connected with several 

 nozzles adjusted so as to play at proper angles on the animal. Dipping is probably the 

 most speedy and effective method to use on a large scale, and especially for thick-haired 

 or woolly animals, and for this purpose receptacles ranging all the way from a small tank 

 for the treatment of a single animal at a time up to a large tank, including two or three 

 dozen sheep at once, may be used. The ingredients for these washes have consisted 

 mainly of tobacco, sulphur, lime, tar, kerosene, and arsenic, and each of these materials 

 will be found to have its advocates. 



Special formulas for their combinations have heen published in abundance, and need 

 not be repeated here. Aside from these published formuUe there are difierent prepara- 

 tions on the market, some of which are doubtless valuable, and if the item of expense is 

 considered satisfactory, it is perhaps proper to recommend their use. Kerosene emulsion 



