'MISSISSIPPI GUARDS' AND 'WORM FLIES.'

Extract of a letter to the Editor of the Saturday Evening Post, dated Columbus, (Miss.) Nov. 16, 1828.

In looking over the pages of the last No. of the Evening Post, (Oct. 25,) my attention was particularly arrested by a piece headed 'Mississippi Guards.' As the subject of it is to me, as well as a number of my fellow citizens, entirely novel, pains have been taken to make particular enquiry of the subject, but can learn nothing of this famous fly. I have resided nearly several years in this State, and the greater of the time in Columbus, which town is situated upon a sand knowl- such a one as these 'guards' are said to select for their stations-and have, until now, been a stranger to the existence of such insects. I can assure you that, for the blast years mentioned they must either shifted quarters or have been entirely negligent of their duty. If the first, it could not have been for want of employment, for in no state are to be found more of that troublesome insect (the horse fly, in all its various species,) than here, they particularly abound in the Choctaw nation of Indians, adjoining us.- We have, however, been plagued during the last summer and even to the present time, though several severe frosts have intervened, with a fly that seems to look upon the horse fly only as its pioneer, to commence work for the other to complete.

The fly alluded to is, perhaps, twice the size of a common horse fly-nothing remarkable in its appearance-its body of a greyish [sic] cast from the neck or joint of the head, to a little beyond the wings--say to where the body divides-the after part is of a changeable bluish green, and covered with very fine black furze; its legs are also so covered. Upon opening one of them, I found it filled with little worms or mites: through them it causes destruction in many instances among the cattle, and several instances are known in this vicinity of their depositing them in the human species. From observation and information, this fly appears at hand when the horse fly draws his proboscis from the horse, cow, or whatever it attacks, and that moment its follower darts upon the fresh blood and deposits its worms, and in less than forty-eight hours, millions apparently can be discovered by the naked eye in the wound--if let alone they destroy the animal. It is worthy of remark that these insects do not interfere with any other than a fresh wound, and one that is merely sufficient to bring the blood to the surface invites their attention. Numbers of cows, hogs, and sheep have been destroyed by them, in spite of exertions used to prevent the increase of the worm. Calomel, mixed with sugar, has been found to be the most effectual experienced upon them. Though they wallow sometimes in this before it purges them from the wound. I have been unable to obtain any satisfactory information relative to the origin of this worm fly, as it is now called, but have been informed they are found in South America in large quantities; and a friend who has returned from the province of Texas, states that they have, for a year to two, been very troublesome there. Is there not a probability that as droves of mules come from these parts, that these troublesome insects may have followed them? I should be pleased if, through the channel of your useful paper, some information might be obtained on this subject.- I am inclined to think that the said fly has confined itself pretty much to the South, at least I have heard from no other quarter of their depredation.

Once more to the 'Guards' I should be pleased if they would return to us, for during their season there is much for them to do.

You will excuse my troubling you; - a desire to obtain useful information for the community will be a sufficient apology, I hope.

Very respectfully, your ob't. serv't.

CHARLES H. ABERT.