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138 INSECTS AFFECTING DOMESTIC ANIMALS. 
of a case where it has occurred in serious numbers. It is listed by 
Osten Sacken, on authority of Kirby and Loew. 
It is of course possible that the species may multiply so as to become 
a pest, and this possibility should be recognized. It might, from the 
ability to fly, be more difficult to handle than the sheep tick, but doubt- 
less the careful grooming of horses affected would prevent undue 
increase. Dusting pyrethrum in the hair would be useful, and this 
could be resorted to with horses in pasture as well as those that are 
stabled. 
THE SHEEP TICK. 
(Melophagus ovinus Linn.) 
Linneeus described this species in 1761 under the name of Hippobosea 
ovinus, but in the later division of this genus, which at first covered 
all the forms included in the family, this species was assigned to the 
genus Melophagus. 
It differs from the other members of the family in never possessing 
wings. The head is small and sunken into the prothorax. The middle 
portion of the thorax is rather 
slender, contrasting with the 
development of this region in 
the winged forms. 
It is of a reddish or gray 
brown color, about one-fourth 
of an inch long, and easily 
detected when present in any 
numbers on sheep. Theynever 
migrate from the original host 
PRON except it be to attach to an- 
AS ag other animal of the same spe- 
Minar cies, 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 considerable dam- 
age, 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. 
Curtice has determined that each female may produce from five to 
eight young, the seed-like brown puparia of which are often to be met 
with among the more numerous adults that adhere to the wool or skin. 
Fie. 74.—Melophagus ovinus: a, adult; b, puparium— 
enlarged (original). 
