B O T 



B O T 



faces of tKefe membranes, and of exciting alio a degree of 

 inflammation in tlicm vvhcie they rcll, fo as to caufc a fccre- 

 tion of lymph or pus for their food. 



" I have moftly found thtfe animals in the horns and 

 frontal fmufes ; though I have remarked that the membranes 

 lining tliefe cavities were hardly at all inflamed, wliile thofe 

 of the maxillary fnuifes were highly fo. From this 1 am led 

 to fulpcrt they inhabit the maxillary iinufes, and crawl, on 

 the death of the animal, into thele fituations in the horns 

 and frontal (inufes. 



" The breeds of thefe, like the oe. bovh, do not appear 

 confined to any particular leafon ; for quite young and full- 

 grown larvx may be found in the Iinufes at the fame 

 time . 



" When full grown, they fall through the nollrils to toe 

 ground, and change to the /)ic'''^ Hate, lying on the earth, 

 or adhering by the fide to a blade of grafs. The fly bnrlls 

 the (hell of the pupa in about two months. The figure is 

 given in the plate ; and its delcription at the conclufion. 



" The manner in which this fpecies depofits its ova, which 

 we have often feen, has not, we believe, ever been def- 

 cribed ; nor is it eafy to fee, though Handing clofc to the 

 animal at the time, exadtly in what way this is accomplidied, 

 owing to the obfcure colour and rapid motions of the fly, and 

 the extreme agitation of the ilieep ; but from the motions of 

 the fliecp afterwards, and the mode of defence it takes to 

 avoid it, there is little doubt tl'.at the egg is dcpoiited in the 

 inner margin of the nollril. 



" The moment the fly touches this part of the fheep, tliey 

 fhake their heads violently, and beat the ground with their 

 feet, holding their nofcs, at the fame time, clofe to the 

 earth, and running away, earnelUy looking on every fide, to 

 fee if the fly purfues : they alio may lometimes be feen 

 fmtlling to the grafs as they go, leall one Ihould be lying in 

 wait for them ; which if they obferve, they gallop back, or 

 take fome other direction, as they cannot, like horles, take 

 refuge in the water : to defend thcmlelve.s againll its attacks, 

 they have recourfe to a rut, or dry dully road, or gravel-pits, 

 where they crowd together during the heat of the day, with 

 their nofes held clofe to the ground ; which renders it dif- 

 ficult for the fiy, who makes his attacks on the wing, to get 

 at the nollril. 



" I imagine the nollril, from repeated attacks of the fly, 

 and the confequent rubbing agaiuft the ground, becomes 

 highly irritated and fore ; which occafions their touch to be 

 fo much dreaded by the flieep. 



From the difficult and very precarious mode thefe flies 

 purfue, and alfo the bizmorrhoulalis, in depofiting their eggs, 

 they cannot fucceed in depofiting but a lew ip each flietp ; 

 whereas, on the contrary, if they aftualiy entered thole 

 cavities of the face to eflcdl it, they mufl depolite them all, 

 and in one fubjeft, the impofiibihty of which is already 

 flated. 



" General ohfervatlons on the oejlri. Having traced thefe 

 feparately through their various changes, and mode of 

 propagation, it may not be improper to confider their good 

 or ill tifefts on the animals that are fubjeit to them. 



" Though the attention of natiiraliils is at prelent occupred 

 with the formation of a nomenclature, and defcriptions, to 

 every objedl of natural hiitory, yet this purfuit, though 

 difficult, and highly important, is not fo much the ultimate 

 aim of this fcience, as a knowledge of their economy and 

 properties ; as it is from thofe we are taught the moll 

 effettual means of avoiding the conftqueiices of the in- 

 jurious, and of protefting fuch as can be ufefully applied to 

 the purpofes of mankind. If afte,r mature inquiry, the 

 exiftence of the oeflri ihould be proved, in a greater degree, 



injurlou.i, than beneficial, by any feivice they can afford, their 

 numbers might be conliderably reduced, and a total ixtirpa- 

 tion of fome of the fpecies would not, I am dilpolid to be- 

 lieve, be altogether impraiflicable in our infular fituation. 



" The injury derived from their depred-dtions is prir.cii)ally 

 felt by the tanner*, w!iofe hides are often fo perforated by 

 thele animals, as to be conliderably damaged ; and fome- 

 times the lofs of a horfe or Iheep may be occafioned by the 

 exillence of the other fpecies. 



" If it were defirable to KIRn their numbers, the following, 

 I apprehend, would be the moll fiiecefsful means. The 

 larv-.e of the oe. bovis, or ox bot, wlweh breeds in the backs 

 of the horned cattle, is fo confpicuous, that it ie more 

 eafily deflroyed than tl;c otliers : the injection of any very 

 corroiive liquor into the limis would kill it ; or by punCturing 

 the larva with a hoi netdle, through the aperture in the (Icin, 

 or even by Ample prefliire, they may be dellroyed, afterwards 

 extraCling them, or leaving them to (lough away, which I 

 have often obferved they do, when cruflied by a blow frnin 

 the horn of the beall, or by any other accident, without the 

 leall injury to the animal. A man employed for this 

 purpofe might, in half a day, dellroy every bolt on a large 

 common, tlie bealls being fuffcred to pal's by him one by 

 one. 



" In refpeft to the great and fmall horfe-bot, thofe who 

 have horles wliich have been rr.uch out to grafs the pre- 

 ceeding year, in countries where thefe flics are prevalent, 

 might conliderably diminidi their numbers, by e.xamining the 

 horles occafionally for the bots, during the iummer months ; 

 when they will be found hanging to the extremity of the 

 reClum, where they remain, efpecially X.\\c htemorrho'ulalis, for 

 fome days before they fall to the ground. 



" The deflrudion of a fingle one, at this feafon of the 

 year, is not only the death of an indi\idual, and its effefts, 

 but the almolt certain dcftruftion of a numerous family. 



" I am induced the more particularly to recommend atten- 

 tion to this circumilanee on another account, 'which is from 

 the neecflity there is of preventing the irritation which this 

 animal occafions to the anus of the horfe, which at times is 

 highly troublefonie. If the horfe is ufed on the road, while 

 the bots are adhering to this part, the irritation becomes 

 particularly di II reffing, andcaufts him to move very aukwardly 

 and fluggifh, as though tired ; and, if feverely beaten, he 

 foon relapfes again into the fame awkward way of going ; 

 and as this generally happens during warm weather, it is 

 attributed to mere lazinefs, and fevere correction follows, 

 but to no purpofe, of which we have two or three times 

 been an eye witncfs ; but, on the removal of the bot, the 

 cure is initantaucous. 



" There is no medicine at preftnt known tliat will detacll 

 them from the ilomach, or intellines, though there are not 

 wanting abundance of infallible nollrums for this purpofe 

 among the very numerous profelfors of horfe medicine. An 

 eafy and cfleCtual mode tor the oe. equ'i, is to dellroy the 

 eggs which arc depofited on the hairs, and are icadily 

 feen and removed by a pair of fciflars, or a brufh and warm 

 water. 



" In the (heep, it would be much more difficult to prevent 

 or dellroy them by any of thele meaivs, particularly if they 

 are fituated in the maxillary finufes ; as, in this cafe, even 

 trepanning them would be infufficient, as they would pro- 

 bably lie concealed in the convolutions of the turbinated 

 bones. 



" Perhaps the removal of the (heep to a diftant pafture, 

 during the months of June and July, whilll the greateft part 

 of the bots are yet on the ground, in a chryfalis (late, and 

 not biinging thi.m on fucli ground again, till the felting in 



of 



