J/f/r. 2, 1908.1 Agricultural Gazette of N.SJF. 231 



epidriiiic which kihed au iiiniu'iise iiuiiihei- dt' Ikhscs in Italy in 1713, as 

 many of the horsns dissected were found to have their stomachs full of these 

 larvje At the present time, most authorities agree tliat a horse infested 

 with bot-flies in any quantity (and as many as -tOO have lieen taken out of 

 the stomach of a horse), will lose tlesh and waste away. Yet it is very 

 rarely that a horse dies from bots ; but where a hnrse has some other organic 

 disease, the two combined may cau.>-e its death, and the bots being found 

 covering; tlie walls of the stomach, are credited witli being the sole cause of 

 its death. Thi-re can be no question that the local irritation caused by these 

 larvie, each attached to the membrane by a double hook at the tip of its head. 

 must be very great, though entire perforation of the stomach is very rare. 



Life History. — The eggs are dull light brown to diity white in colour, 

 elongate oval in form, somewhat pointed, and broadest at the apex. The fly 

 d(!posits them singly upon the hairs, the shell being coatefl with a sticky 

 substance that glues them on, so that it is a difficult matter to pull them off. 

 I have had hair taken off an infested horse with hundreds of them, but never 

 saw one hatch out in the jars in which they were kept. These eggs are 

 generally deposited on the jaw, shoulders, or flanks of the animal, from 

 whence, through the animal licking itself, they are conveyed to the lips and 

 motith, the warmth dissolving the gluey secretion and hatching the enclosed 

 maggot, thus enabling it to crawl out into the throat, from which it gains 

 access to the stomach, and takes up the position which it retains, attached to 

 the coating of the stomach until it is fully developer), when it looicns its 

 hold and is carried through the intestines and voided with the dung ; but 

 very soon afterwards it works its way downwards and buries its^-lf in the 

 soil, where it pupates, and from which the perfect fly emerges in about six 

 weeks in the summer time ; but the final development is retarded or 

 accelerated by the time of the year in which they are cast out. 



The larvfe vary from dull yellow to light reddish-brown, and are of a 

 general oval form, measuring up to | of an inch in length and 5 lines in 

 diameter in the centre. The head portion is attenuated and armed with two 

 stout hooks placed back to back, each curving otitward, with the mouth 

 between them, and, when in position, these hooks and the mouth are buried 

 iti the membrane of thestanach, causing a pit or scar to form, which shows 

 quite distinctly when the bot is detached The segments of the larva? are 

 very well defined, and eacli is ringed with a band of i-egular, short, fleshy 

 spines, tipped with a black point, which, together with tlie cephalic hooks, 

 are very distinctive characteiistics of the bot, by which it can be easily 

 recognised. 



The fl}^ is about half an inch in length, the male having the abdomen 

 broad and rounded at the tip, but that of the female is slender and elongated, 

 and is generally c^rried curled down beneath the base of the body. The 

 h'^ad is dark yellow, thickly clothed with short golden-3'ellow down ; the 

 thorax clothed with fine pale yellow to light brown hairs or dow^n, which 

 gives it the appearance of a hairy bee. The abdominal hairs are lighter 

 along the sides, and intermixed with shorter black ones on tlie dorsal surface 



