160 
THE BOT OF THE HORSE. 
deposit them upon the hair of the nostrils, the lips, and the 
cheeks. There they deposit their eggs, in order that, being 
ready to hatch, through a sort of incubation effected in the 
egg, they more readily find their first place of lodgment. 
The hypoderm.es accomplish their metamorphoses at the end 
of the spring, at the very period when the large ruminants 
are changing their coats, when it is easier for the insects to 
perforate the skin with their oviduct, to deposit their eggs in 
it. The larvae of all the oestri have a conical form ; their 
mouth is fortified on the sides with horny hooks, by means 
of which they fasten into the mucous membrane and cellular 
tissue; and between the tenacula or hooks, they possess 
an organ of suction, which varies according to the species. 
The rings around their body are clothed with downy hair, 
rigid and thin, which performs the office of locomotive 
organs ; these hairs changing their direction on the posterior 
segments. In some species, at the most bulky end of the 
body, there exist stigmata. 
In humid, cold autumns, many female oestri of horses die 
without laying any eggs ; on the contrary, during hot and 
dry autumns they become quite a plague to animals. At 
such seasons, all quadrupeds at liberty retire into the thick of 
bushes, in the depth of forests, where they rest during the 
heat of the day. Should the pastures be without hedges or 
bushes, they will ascend elevated spots, where they find 
more current of air, and there pass the day, to descend after 
the heat is over ; or, in the absence of such rising grounds, 
where rivers or streams of water are to be found, horses will 
call one another together, about ten o’clock in the morning, form 
a troop, elect a site where the water is shallow or where there 
happens to be an eddy, and turning their quarters to the wind, 
endeavour with the feet and the tail to make a splashing in 
the water, and thus deliver themselves from the torment of 
the oestral flies, who fortunately shun humidity. 
Woe be to the traveller who, in Sardinia, on the Pyrenees, 
in Sicily, &c., suffers himself to be taken by surprise on 
horseback, during the time the sun is out, in the month of 
October: he runs a risk of being unhorsed, especially should 
he happen to pass some woody part where such flies have 
assembled in great numbers. The only expedient in that 
case is to take snuff or chew tobacco, or to wrap up some of 
either in one’s handkerchief, dip it in the water, and rub the 
horse’s skin with it ; the odour of it scares the flies, and they 
make their escape. Those who take snuff ought to throw 
some into the nostrils of the horse, for insects which are 
unable to lay their eggs upon the hair will endeavour to 
