THE BOT-FLIES. 
G23 
hooks ; and the rings of the body are surrounded with 
rows of smaller hooks or prickles. When they arc fully 
grown, they drop to the ground and burrow in it a short 
distance. After this, the skin of the maggot becomes a 
hard and brownish shell, within which the insect turns to 
a pupa; and finally to a fly, and comes out by pushing off 
a little piece like a lid from the small end of the shell. 
More than twenty different kinds of bot-flies are already 
known, and several of them are found in this country. 
Some of them have been brought here with our domesti- 
cated animals from abroad, and have here multiplied and 
increased. Three of them attack the horse. The large hot- 
fly of the horse ( Crasterophilus equi ), (Plate VIII. Fig. 2,) 
has spotted wings. She lays her eggs about his knees ; the 
small red-tailed species ( Cr. hcemotrhoidalis ) on his lips ; 
and the brown farrier bot-fly (Cr. veterinus) under his throat, 
according to Dr. Roland Green. By rubbing and biting the 
parts where the eggs are laid, the horse gets the maggots 
into his mouth, and swallows them with his food. The in- 
sects then fasten themselves, in clusters, to the inside of his 
stomach, and live there till they are fully grown. The fol- 
lowing are stated to be the symptoms shown by the horse 
when he is much infested by these insects. He loses flesh, 
coughs, eats sparingly, and bites his sides ; at length he has 
a discharge from his nose, and these symptoms arc followed 
by a stiffness of his legs and neck, staggering, difficulty in 
breathing, convulsions, and death. No sure and safe rem- 
edy has yet been found sufficient to remove bots from the 
stomach of the horse. The only treatment to be recom- 
mended is copious bleeding, and a free use of mild oils, in 
the early stages of the attack. The preventive means are 
very simple, consisting only in scraping off the eggs or 
nits of the fly every day.* 
* See Dr. Green's “Natural History of the Horse-Bee,’’ in Adams’s Medical and 
Agricultural Register, Vol. 1. p. 63; and the same in the New England Farmer, 
Vol. IV. p. 346. 
