225 Indian Museum Notes. [Vol. IV. 



at different times by rubbing them with a moistened finger, simu- 

 lating as nearly as possible the action of the tongue in licking the 

 body. While the larvae appeared to be fully formed during the 

 first three or four days after deposition, the eggs hatched with 

 difficulty and the larvae seem quite inactive, and all larvae that were 

 freed in this manner up to the tenth day were hatched with difficulty, 

 though the larvae at the end of this time were becoming fairly 

 active. 



Four weeks after hatching the eggs opened with the slightest 

 touch of a wet finger, and the larvae adhering to the finger were 

 very active, though in some cases they were inactive and apparently 

 dead. About five weeks after collecting the eggs nearly all gave 

 only inactive or dead larvae, though opened with ease on being 

 touched with the finger, and in forty days after collecting no living 

 larvae could be found in the remaining eggs, except one which had 

 succeeded in pushing off the cap of the egg and partially emerging. 



In view of these results, I conclude :— > 



(i) That the eggs of the horse bot-fly do not hatch, except by the assistance 

 of the horse's tongue. 



(2) That hatching does not ordinarily occur within ten or twelve days and 

 possibly longer, or if during this period, only on very continuous and active 

 licking by the horse. 



(3) That the hatching of the larvse takes place most readily during the third 

 to fifth week after deposition. 



(4) That the majority of the larvse lose their vitality after thirty-five to forty 

 days. 



(5) That larvse may retain their vitality and show great activity upon 

 hatching as late as thirty-nine days after the eggs were deposited. 



(6) That it is possible, though not normal, for eggs to hatch without moisture 

 or friction. 



(7) That in view of these results, the scraping off of the eggs, or their removal 

 of destruction by means of washes will be effective even if not used oftener than 

 once in two weeks during the period of egg deposition, and, probably, that a 

 single removal of the eggs after the period of egg deposition has passed,will prevent 

 the great majority of bots from gaining access to the stomach, or at least so large 

 a proportion that little injury is likely to occur. 



Wishing to know still more definitely the period of most ready 

 hatching, and the effect of different washes for treatment, I suggested 

 to a veterinary student, Mr. Harry Shanks, a careful series of 

 observations, which were carried through during the summer of 1894. 



From this study, which was made under my direction, and so 

 that I had frequent opportunity to note progress, a number of points 

 were gained, which are worth adding to the above record. Three 

 hundred eggs were collected from a horse which had been previously 



