ORDER SIPHON APTERA 289 



ber on sheep. They never migrate from tJie original host 

 except it be to attach to another animal of the same species, 

 and probably the principal movement is that which occurs 

 after sheep are sheared, when the ticks tend to migrate to 

 lambs. On the sheep, if abundant, they may cause con- 

 siderable (himage, indicated by lack of growth or poor 

 condition, and when massing upon lambs they may cause 

 great damage, resulting in the death of the victims if not 

 promptly relieved. 



They are distributed over the world generally where 

 sheep are kept, and are too well known by sheep breeders 

 to make it necessary to emphasize the injury they may 

 cause. All breeds of sheep seem alike subject to attack, 

 but I know of no record of their occurrence upon other 

 animals. 



While the ticks may be greatly lessened in number by the 

 vigorous use of pyrethrum — a most available remedy during 

 winter — the most practical plan to adopt, and one which if 

 thoroughly followed will make all others unnecessary, is to 

 dip the sheep each year after shearing. 



A flock once freed from the pests will not be again infested 

 except by the introduction of infested animals: hence care 

 should be taken in making additions to the flock to free the 

 newcomers from parasites. It is also well to keep the sheep 

 for a few days after dipping in a different inclosure from 

 that occupied before, to avoid possible infestation from any 

 stragglers that may have been caught on wool upon posts 

 or brush, and if the wool is charged with them when clipped, 

 it should be stored where the ticks could not easily return to 

 the sheep. The ticks cannot travel any distance inde- 

 pendently, and will soon die when removed from the sheep, 

 and proper care here will insure success. 



Order SIPHONAPTERA. 



Another order is the Siphonaptera. The fleas are wingless 

 or have the wings so aborted that they are practically wing- 

 less. Vestiges of wings may occur but are useless as organs 

 19 



