4:1 



liy Ki-aziiig the dangerous land exclusively with young cattle, or with cattle 

 which have been for at least one season on such land. This plan, is, however, 

 not free from risk, for although an animal may have been grazed as a calf 

 on dangerous tick-infested ground, it may have accidentally escaped infection, 

 and thus failed to acquire immunity. The probable consequence would be that 

 when this same auluial returned to the pasture next season it would contract 

 the disease in a dangerous form. To counteract this risk, the owner might 

 assure the infection of bis calves, or of such of them as were afterwards to 

 be grazed on the dangerous pasture, by having them inoculated with the blood 

 of an animal known to have recently recovered from an attack of red-water, 

 as experience shows that this is an operation attended with little or no risk 

 in the case of animals under six months old. 



In conclusion, it ought to be pointed out, however, that all animals which 

 have thus been vaccinated against red-water, and all those which have been 

 grazed on infected pasture, are capable of carrying the seeds of the disease 

 to pasture previously healthy, provided they carry ticks with them or ticks 

 are already there. This danger scarcely exists in moving infected animals to 

 land suh.lect to rotation of crops, for ticks cannot there permanently establish 

 themselves, but the risk is a very real one when infected cattle are moved to 

 permanent pasture or moorland. — Journal of Roinil Af/riciiUiiral Society of 

 EiKiJund, Vol. 6S. 



Horse Bot-Fly {GastiophiUis cijiii. Fab.). 



Bots in horses have been a familiar form of parasite to farmers, stock- 

 men, and veterinarians for we know not how long. ^Yhether they were 

 familiar to the ancients has been a matter of discussion among learned men. 



Adults of this species are about three-fourths of an inch in length; the 

 wings are transparent with dark spots, those near the centre forming au 

 irregular, transverse band. The body is very hairy, the head brown with 

 whitish front, thorax brown, abdomen brown with three rows of blackish 

 S|)ots. which are subject to considerable variations. lu the females the 

 segments are often almost entirely brown with simply a marginal series of 

 yellowish spots, while in males the abdomen may be almost entirely yellow 

 or very light brown, with brown or dark spots very distinct. The males are 

 rarely seen, for while it is one of the most common occurrences to witness 

 the females around the horses, depositing their eggs, the males evidently hold 

 aloof. The eggs are light yellow in colour, and will be found attached to 

 the hairs of the shoulders, forelegs, underside of body, and .sometimes even the 

 mane and other parts of body, most commonly, however, on the forelegs and 

 shoulders. The method of deposition has been frequently observed. The 

 female hovers near the horse in a position which appears to be nearly vertical, 

 since the body is bent downward, and the extended abdomen is thrust forward 

 under the body to its full extent. The fly then darts toward the horse, the 

 egg is glued to the hair in an instant, and the fly retreats a yard or two to 

 hover till another egg is ready to be deposited. The eggs are held by a sticky 

 fluid, which quickly dries and thus glues them firmly to the hairs. 



In dealing with bots in horses, by far the most important point is to pre- 

 vent the introduction of the larv», and while we have no opportunity, as in the 

 case of the ox bot-fly, to completely exterminate the pest, it is certain that 



