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 

 from nose flies, al- 

 though it would not 

 prevent infestations 

 by the other species 

 of G as t r ophilus. 

 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 larvse are small, or whether they 



Fig. 4. — A bot preventive. The box prevents " nose flies " 

 from ovipositing when the head is held upright, while the 

 block of wood underneath the box allows the horse to 

 graze easily. The canvas prevents normal ovipositions of 

 the " throat bot-fly," and does not permit the horse to 

 bite the portions infested with eggs of the " common bot- 

 fly." (Original.) 



