GASTROPHILUS HAEMORRHOIDALIS AND OTHER BOTS. 45 
stituting a hard wood. The weight in either case will compare with 
the weight of blind bridles. Horses using these in experiments be- 
came free of G. haemorrhoidalis eggs during the summer of 1916, 
whereas unprotected animals were heavily infested. There was also 
a marked difference in the feeding, as protected animals grazed nor- 
mally in_ bunches. 
While the device in- 
dicates a favorable 
preventive measure, 
before its adoption 
tests of durability 
should be made and 
minor points in the 
construction deter- 
mined. It seems pos- 
sible that the con- 
struction could be 
made so simple that 
farmers could make 
the protectors at a 
nominal price. 
A halter attach- 
ment would permit 
horses to graze dur- 
ing times ‘that are 
favorable for depo- 
sitions of flies, and 
would prevent even- 
tual infestations by 
all three species of 
Gastrophilus. A 
shed constructed in 
the pasture would 
protect animals 
; Fic. 4.—A bot preventive. The box prevents ‘nose flies ” 
from nose flies, al- from ovipositing when the head is held upright, while the 
though it would not block of wood underneath the box allows the horse to 
. : graze easily. 'The canvas prevents normal ovipositions of 
prevent infestations the ‘‘throat bot-fly,’ and does not permit the horse to 
by the other species bite the portions infested with eggs of the ‘‘common bot- 
3 fly.” (Original.) 
of Gastrophilus. 
Such a shed would keep the animals from grazing during times that 
were favorable for depositions, and could be used for storage of feed 
during the winter. 
EFFECTIVENESS OF WASHES UPON EGGS. 
Regardless of whether horses are treated internally for bots, which 
is best during the autumn, when larve are small, or whether they 
