NEW ENGLAND FARMER. 



Published by John B. RcssBtL, at the corner orCongross and Lindall Str?e;^.— Tnn-.,.s3 G. V^-'^rF.s.-nr.y fid 



VOL. IV. 



BOSTON. 1 R[DAY, MAY 2(>, 1826. 



unr.y, firlitor. 



No. 44. 



ORIGINAL PAPERS. 



Mr Pessf.nden — It \\ill be a eratification to 

 your correspondent, if he shall be able to add any- 

 thing, however small, to the general stock cf 

 knowledge. The following resuU uf i«aftk.experi- 

 ments was communiciledto Dr Auams, w|(|pub- 

 lished it in the-Medical and Agricnltural RifgUtrr, 

 180<). By request, it is now revised, vith sou 

 addition, and presented to you. Di,=;i>i ^ r,'' i; ;, 

 your wisdom shall direct. li. (iREEN. 



Mansfield, .Ipril 24, 182G. 



NATURAL HISTORY OF THE BOT-FLY, i 



WITH A VAP.IETT OF OB9ERVATIO.VS AND EXPERI- | 

 MEKTS, INTERESTING TO THE FARMEK. I 



The Bot fly, (Oestrus Equx,) is a species of in- • 

 sects, which belong to a genus of the order Dip- 

 tera. Their natural history is involved in some . 

 obscurity. There are many concurring circum- , 

 stances, which prevent us from exhibiting a com- 

 plete history ; tlieir economy being diftercnt from 

 that of most other insects. They are, in a certain I 

 period of their existence, placed beyond the scope I 

 of observation ; hence it is very difficult to trace ' 

 them through the several stages (the egg, the lar- i 

 va and the chrysalis) of the imperfect state to the 

 last or perfect. ' 



Many valuable horses have been Inst in coit '> 

 i-iuence of these msec u«, wiiich, while in the la:-va 

 or growing state inhabit the stomach, prey upon 

 it, destroy its texture, and introduce tliseasc and 

 death. From these circumstances, the following 

 observations and experiuieuts were made, hoping 

 that they would lead to the discovery of some ef- 

 fectual remedy. 



Tiie insects in their perfect state, commonly 

 present themselves to our observation ; tlierefore, 

 we shall begin with them in this state, and en- 

 deavor to trace tlieir offspring thro.ugli their vari- 

 ous gradations of " youtli, vigor, and old age," or 

 until they arrive to the perfect insect, wliich is in 

 about twelve months. 



The insects appear toward the end of June or 

 the first of July, but are most numerous in August 

 and September. Few are to be seen after one or 

 two cold evenings. They cannot endure the cold, 

 of course they are not active in the night. 



There are two varieties, one larger than the 

 other. The larger kind are covered with down of 

 a brownish colour with darker shades. The wings 

 two in number, are transparent, having darkish 

 shades. The female deposits her eggs generally 

 on those parts of the horse where he can bite him- 

 self, especially on the anterior legs, but never 

 under his throat. When she approaches the horse 

 she supports her body nearly upright in the air, 

 and with one of her feet bends out a hair, on which 

 she deposits an egg, and thus she continues to do 

 for a short time, and then goes off, probably to 

 rest herself, and then return to her charge. — 

 The smaller kind are covered with a darker and 

 thicker down. Wings transparent and without 

 any shades. The female deposits her eggs under 

 the throat and no where else. As she approaches 

 the horse, instAUtly darts up under his tliroat and 



deposits an egg vrith incredible expedition, and 

 then goes ofi", but soon returns again and again, to 

 the great disquiet and trouble of the liorso, caus- 

 ing him to tlirow up his head with violence. Each 

 kind varies in size, but in general they arc about 

 three-fourtlis of an inch in length. The head, 

 thorax, and abdomen are divided by slender inter- 

 j veiuug portions. The body of the fsraale is larg- 

 I er than tliat of the male, ending in a ponic form, 

 1 which wlien she flies is folded up. From the un- 

 I der side of the thorax proceed six slender legs, 

 the extremities of which are armed with two claws. 



The eggs are fastened to the hair by a strong 

 j glutinous substnnce, which wh.^n dry, neither the 

 I heat of the animal combined' with moisture, nor 

 1 frost will dissolve. They are small, about three- 

 I fourths of a line in length, and of a ligiit yellow 

 I colour; and arc always placed on the hair with 

 \ the largest end downwards. One female of a mid- 

 dle size, was known to coutain 8^tl effgs, a jiumd- 

 . reus increase — this being the last work as? i;;-;ied, 

 ' which when concluded, the male and female per- 

 j ish. 



It has been supposed that the horse's stomach 

 I was the only fit place for the eggs to hatcli, and 

 I that the eggs are taken in by the horse biting liim- 

 I self, &c. but this is not well founded. These eggs 

 j like all others, require a certain time to hatch. — 

 The larva in miniature must have time to expand 

 before it can burst from its confinement ; ajid this 

 t may do, in about QO days* after the egg is dn- 

 ;)osile3 ; "but they do not generally burst the shell 

 so soon, either from cold weather,! (which retards 

 their coming out.and perhaps their growth,) tough- 

 ness of tlie shell, or for the want of pressure. — 

 When the larva is formed, and ready to break 

 from its prison, it seems to wait for pressure, on 

 which the shell is broken at the largest end ; and 

 the i)!sect though very small, appears to be very 

 active. When this minute creature bursts the 

 shell by its own accord, it commonly remains for 

 some time only a part out of the same, waiting 

 perhaps for the horse to take him in. They are 

 now ready to enter the horse's stomach, which 

 they do by the horse biting hiiuself or others ; or 

 they may»fa!l on the grass and be taken in while 

 tlie horse is feeding. Those of the smaller kind, 

 under the tliroat, may travel to, and enter the 

 mouth, and from thence be conveyed into the 

 stomach. 



The young larva; (commonly called Bots) are pro- 

 vided w ith two small sharp hooks, by which, when 

 they arrive at the stomach, tliey take hold, and 

 there prey upon it until they arrive to their full 

 growth ; but fortunately very few, in comparison 

 to the wliole, come to maturity ; most are destroy- 

 ed in their infancy ; yet it is too often the case, 

 that too many remain consistent witli the life of 

 this noble animal. When they are full grown, 

 they are about three-fourths of an inch in length. 



* Scpftmber 2, 1802, placed a number of eg§js jupl 

 deposited in a moderate temperature of heat ; on (ht 

 30th four batched, and on October 2d two more came 

 out by pressure ; others hatched not so soon. 



t January, 1802, after severe frosty ■weather, ejs;»s 

 were taken from a horse and placed in a warm room ; 

 some hatched in five days, others in twelve. Eggfs de- 

 posited in September may not batch uutil the spring 

 folio win". 



and nbont one fourth of an inch in diameter at the 

 truncated or larger end, which has every appear- 

 ance, to the :>? ked eyes, of being the liead of tlie 

 insect, but the reverse of this is true. The small- 

 er end, whicii is somewhat pointed, is the head, 

 froir> which pr_ve3u the two hooks, by wliich they 

 iiOhl fast. They are covered with a thick tougii 

 skin, of a pale yeilow-islr colour. From the head 

 there are ten segment*, which seem to be a chain 

 of annuliU' muscles, whose fibres being contracted 

 render the segments more narrow, and by ti:e:=e 

 means, move from place to place ; stretching for- 

 wards, and taking hold vwti! their hooks, and then 

 contracting tLemseives, which carries them on- 

 ward ; tlien unfasten and stretch again, and so on. 

 In the anterior part of the segments, e.Kcept the 

 two posterioi portions, are set numerous small, dark 

 coloured, sharp points or thorns, projecti.ug back- 

 wards, which prevent tiiem from slipping back 

 when moving. They liave uo feet. 



Thoy penetrate tlirongh ihc villous into the mus- 

 cular coat of tfe stomach, forming small cavities 

 in tiie same, and there hang by their hooks, irri- 

 tating and wounding the auimal. If at any time, 

 they lose their hold, they inmiedi'.tely catch again. 

 Not any part of, the stoniacli is exempted from 

 them ; but they are most numerous near the pas- 

 .^ages into and Q,ut of the stomach. They are of 

 all insects ti;- most te«acious of life, at tliis peri- 

 od : and at » ij time of their existence it is tliat 

 they -[nvrroj -l.-./ ittotruciive to horscss • 



Those horses that are lost by the insects; most 

 commonly die in the i.'.onths of February, March, 

 or April; however, this depends on tlie. number 

 ind growth of the insects, and the injury done to 

 the stomacli. How long it is necessary for theni 

 to dwell in the stomach is unknown ; but in the 

 months of May, June and July, especiall}' the two 

 latter, they pass the intestines, and immediately 

 seek refuge in the earth at an uncertain depth, 

 according to the hardness of the soil, not deep 

 hovi'evcr. At this time they are of a light colour. 

 The second or third day after they go into the 

 eartii, they become contracted in length, less ac- 

 tive, and of a light mahogany colour. In one or 

 two days more, stiff, hard, and a still darker col- 

 our. They have now passed the larva state (the 

 state of growth) into the chrysalis or aureiian state, 

 (the state of torpor) and are rather mor^^ than half 

 an incli in length and nearly one fourth of an inch 

 in diameter, oblong, motionless, and the hooks and 

 points almost obliterated. They do not cast ofT 

 the skin, (which becomes a shell) as many other 

 insects do, when they pass into the chrysalis state. 

 The wings when formed, are folded up, but expand 

 when they arise to nev/ life. In about thirty days 

 after tiiey enter the earth, the fly or perfect insect 

 breaks the shell near its smallest end, and comes 

 out of its confinement, a -renovated creature;— 

 "every thing is changed, all its powers are new, 

 and life to it is another thing." With certam in- 

 dividuals there is some variation as to the length 

 of the aureiian period, from certain causes it may 

 be protracted beyond the usual term of thirty 

 days. They have no proboscis. They receive no 

 food in the chrysalis stage, and it is probable that 

 they receive none in the perfect state, being doom- 



