58 *tHB HORS^. 



tion to eat any thing within reach. They sometimes have repeated at- 

 tacks of colic, which recover abruptly; and the animal assumes a 

 position to relieve pain— sitting on haunches, 01 standing with front feet 

 on an elevation. There is no effective remedy, all that can be done is 

 to give physic to move the bowels, to relieve pain, and to combat the 

 inflammation. 



Bots — I/arvae of the Gad-fly. There are so many wrong opin- 

 ions concerning the bot and the harm it is supposed to do the horse, that 

 we give it considerable space. Of the many insect parasites and other 

 tomentors of the horse, mule, and other solipeds, the gad-fly is of the 

 most importance. Cobbold, who it the best authority on the subject, 

 says: 



"The common gad fly attacks the animal while grazing late in the 

 summer, its object being not to deri\'e sustenance, but to deposit its 

 eggs. This is accomplished b}- means of a glutinous excretion, causing 

 the ova (eggs) to adhere to the hairs. The parts selected are chiefly 

 those of the shoulder, base of the neck, and inner part of the fore-legs, 

 especially about the knees, for in these situations the horse will have 

 no difficulty in reaching the ova with its tongue. When the animal 

 licks those parts of the coat where the eggs have been placed, the mois- 

 ture of the tongue, aided by warmth, hatches the ova, and in something 

 less than three weeks from the time of the deposition of the eggs the 

 larvae have made their escape. As maggots they are next transferred 

 to the mouth and ultimately to the stomach along with food and drink. 

 A great many larvae perish during this passive mode of immigration, 

 some being dropped from the mouth and others being crushed in the 

 fodder during mastication. It has been calculated that out of the many 

 hundreds of eggs deposited on a single horse scarcely one out of the 

 fifty of the larvae arri\'e within the stomach. Notwithstanding this 

 waste the interior of the stomach may be completely covered (cuticular 

 portion) with bots. Whether there be few or many they are anchored 

 in this situation chiefly by means of two large cephalic hooks. After the 

 bots have attained perfect growth they voluntarily loosen their hold and 

 allow themselves to be carried along the alimentary canal until they es- 

 cape with the feces. In all cases they sooner or later fall to the ground 

 and when transferred to the soil they bury themselves beneath the sur- 

 face in order to undergo transformation into the pupa condition. Hav- 

 ing remained in the earth for a period of six or seven weeks, they final- 

 ly emerge from their pupal-cocoons as perfect dipterus (winged) msects 



