as affecting Domesticated Animals. 43 



The means at our disposal for getting- rid of ticks are simple 

 and efficacious. They should not, however, be pulled off, unless 

 existing in twos or threes, for by such means the rostrum will be 

 left fixed in the skin, and may give rise to untoward results. Mr. 

 Blaine, in his ' Canine Pathology,' recommends that the parasites 

 be clipped asunder with a pair of scissors, when they will, he 

 says, immediately retract their sucking organ and fall off. 



Sponging the skin with a decoction of tobacco, saturated with 

 salt, will generally cause them to quit their hold. A mixture also 

 of linseed-oil and creasote, made with one oz. of the latter to 

 four of the former, rubbed in with the point of the finger around 

 the part where the ticks are placed, will be effectual for their 

 removal. They are likewise very easily destroyed by touching 

 them with oil of turpentine, but it generally happens that they 

 still retain their hold ; this, however, is a matter of little im- 

 portance, because after death they can readily be detached, by the 

 slightest friction, and will then be found to come away entire. 



Melophagus Ovimis. — Sheep-Tick. 



Although commonly called a tick, this well-known parasite 

 belongs to a very different order of insects. Its natural history 

 is so replete with interest that it may be affirmed the scientific 

 investigator feels an ardour in his researches which is only sur- 

 passed by the desire of the practical agriculturist to rid his flock 

 of this troublesome visitor. 



The natural history and mode of development of the Melo- 

 ])hagus agree with those of the Hippohoscites, a variety of the 

 Diptera, although, like many other genera, the Melophagus is 

 entirely devoid of wings. Its metamorphosis is perfect, but 

 not completed in the same visible and well understood manner 

 as in most insects which undergo this change. Thus the larva is 

 produced from the ovum icithin the body of the parent^ and 

 changed likewise into the ■pupa before being expelled from her 

 uterus. Insects undergoing a metamorphosis of this kind are 

 iGTvaed j)uj,iparous, in contradistinction to oviparo7is and viviparous 

 creatures, as well as to those which pass thi'ough an ordinarv 

 series of metamorphoses. A single ovum at a time is transformed 

 in the manner described, so that Melophagi multiply only by a 

 series of single births. When first expelled, the pupa is of 

 a yellowish colour, and easily compressible, but it soon acquires 

 a brown hue and considerable hardness. It adheres to the wool 

 very slightly, and principally by the sebaceous secretion of the 

 skin of the sheep. Fig. 3 gives a magnified view of a pupa, by 

 which it will be seen that in its general form it is egg-sliaped, 

 haying, however, one of its ends truncated. 



