Thomas Jefferson Papers

Enclosure: John A. De Normandie to Thomas Jefferson, 24 May 1792

John A. De Normandie to Thomas Jefferson

Burlington May 24th. 1792


The following Observations on the Hessian Fly were made during the Years 1788 and 1789 with a view of investigating their Natural History. The paper from the Committee of the Philosophic Society induced me to furnish such observations as I then made. I fear I have been prolix, but as it perhaps will be impossible positively to prove they are Indigenous, I have added such reasons as induced me to believe they are so which I submit to the Committee, and am with the greatest respect Sir Your most Obedient Humble Servant

John Abm: De Normandie

1. The fly as I have been informed made its first appearance on Long or Staten Island during the time the British were in possession of those Islands: nevertheless the probality is, they are Indigenous in America for reasons hereafter to be assigned.

2. I never could discover theire eggs. In their worm state they are extreamly tender bursting with the slightest handling, about one sixth of an Inch long, and perfectly white; and the probability is they soon pass thro’ that state, as with the most diligent attention I found but few in it. As in their several stages they observe the same laws with those of the Moth, is it not probable that like them they propogate but once. To obtain their perfect history, I apprehend will be difficult, as after coming out of their Chrysaline state I never could get them to couple, tho every provision was made for their accomodation. After leaving their shell, they immediately flew to the window endeavoring to make their escape, and in about five days died. In this part of the Country, the brood that does the injury is laid in the fall of the year on Wheat, Rye, and Timothy grass, the only vegetables on which I ever discovered them, and that, after the plants had acquired three or four leaves; during the fall of the year the eggs hatch and the worm passes into its Chrysaline state, in which it continues during the Winter, which when remarkable severe, destroy great numbers; such as survive enter their fly state sometime in April.

3. All sorts of Wheat are subject to their impression except that kind of bearded Wheat whose stalks are almost solid, which they have not injured, but numbers of Farmers have suffered from sowing other sorts. In this part of New jersey spelts are not raised. I never observed the roots to be injured, neither do they affect the Farina or leaves. The part of the stalk to which they confine themselves in the fall, is the joint just above the root, but in the spring, I have found them in the joint above, but these have appeared a month or Six weeks later than the general crop; in no other part of the stalk have I ever seen them, neither have I ever found them amongst the grain, or heard of their attaching themselves to it. The injury I suspect is intirely done by pressure in the tender state of the plant, whilst the insect is in its Chrysaline state. In its worm state, it has no organs that ever I could discover even with a large magnifier, capable of piercing the straw, neither with the same magnifier could I ever discover the stem had ever been punctured. In the last period of their worm state, they collect themselves just above the first joint close to the root, which they compleatly embrace and so close together as to prevent the sap from rising to nourish the plant, and appears to have the same effect as a Ligature drawn tight round them would have; what appears a further confirmation that from this cause the injury proceeds is, that in all my observations, I found the stem opposite the part in which they had lodged themselves reduced to the size of a small needle, when the parts above it were considerably enlarged. My reasons for supposing them indigenous are, they from every appearance continue but a short time in their egg state. In that of a worm they do not continue long, as the eggs are laid, hatched, and pass thro the worm into the Chrysaline state, after the Wheat has come up in the Autumn, and acquired some growth. In their worm State they appear to receive their nourishment by sucsion, as their mouths are well adapted to that operation. Should they have been imported, it must have been in their Chrysaline state; as the Fly ever deposits its eggs on green vegetables, where as soon as they are hatched, the young brood may have a ready supply of food; the only way in which there is a possibility of theire being brought from Europe is during their Chrysaline state, but in that it must appear evident they could not be imported. On full grown healthy Straw I never have discovered Eggs, Worm, Chrysalis, or Fly, and could it be presumed they were taken on board the Transports in such Straw; the warmth of the Soldiers bodies, as well as the Season of the year in which such people are generally embarked, would bring on the fly state, when for want of green plants on which to lay their eggs, and to afford food for the worm, they must unavoidably perish.

4. I have not seen or heard of their injuring any kind of Spring-grain, or other grass than Timothy, other persons whose researches have been more extensive, may have a better opertunity of answering this question. About four Years past great numbers were observed in my Garden in their fly state; they did no damage, but resorted under some Italien Mulberry trees, and settled on the ground where numbers of the ripe Mulberry had fallen; and under One Tree situate in a moist spot, the greatest numbers collected. I have never discovered them in any other parts of a plant than those already mentioned, and am of opinion they do no injury either in the worm or Fly State.

5. The Fly has been found to commit its depredations equally in every kind of soil, wether Sandy, Gravelly, or Loam. A method persued by some Farmers who have plenty of Stable dung has succeeded equal to their wishes. They prepare theire fallows in the usual manner; Manuring highly before the last ploughing, but defer sowing until some time in October, when the fly has done laying their Eggs, when tho’ late in the Season for Sowing, the warmth and fertility communicated to the Soil by the quantity of Manure put on it, brings on so rapid a vegetation that the Crop ripens at the usual time of Harvest. It is probable the sole benefit arising from this mode is to be attributed to the late sowing, after the flies have laid their eggs, and not to any peculiarity in the dung, either from its smell or any other cause that may have rendered it disagreeable to them.

6. From information, for I have had no opertunity of inspecting Fields sown with the different kinds of bearded Wheat I am told that all the kinds of that grain, except the One whose stalks are almost solid, are as susceptible of the injury from the fly as Common wheat.

7. Persons living near the extreme parts where the fly has committed its depredations can only ascertain the extent of their ravages, but as far as my observations have extended, they appear not to have pursued any specific rout. Taking Long or Staten Island as a Center, from whence they migrated; the Sea would limit them to the South. To the Northward and Westward their progress has been nearly equal, what progress they have made to the Eastward the Friends to this enquiry will no doubt give the necessary information. Their Yearly progress appears not to have been regulated to any particular distance. Near the time of laying theire eggs, they fly in innumerable quantities to a considerable distance to obtain their favorite Wheat, in which to deposit theire eggs, which if found in the vicinity of the place where they assume the fly state, theire progress was more slow.


9. Exclusive of the method of escaping the ravages of the Fly mentioned in § 5 I know of no experiment that has succeeded in preventing the fatal effects of this insect. In the Egg state I have never seen them, in their Chrysaline state they are extremely hard and incapable of being injured from any pressure that could be applyed to them. In theire worm state they are as remarkably tender, and could the precise time be discovered in which they enter that state the probability is the Roller would destroy the whole brood: this precise time must be discovered by constant inspection as it is not to be discovered by the appearance of the wheat, till the mischief is done, and they have been for some time in their Chrysaline state.

RC (DLC); at head of text: “To Thomas Jefferson Esqr. Secretary of State to the United States.”

John Abram De Normandie (1721–1803), a Swiss-born physician and former justice of the peace in Bristol, Pennsylvania, was elected the first president of the Burlington Society for the Promotion of Agriculture and Domestic Manufactures in 1790. De Normandie was also a member of the American Philosophical Society and had obviously seen a copy of the Society’s circular letter on the Hessian fly printed under 17 Apr. 1792 (Franklin, Papers, description begins Leonard W. Labaree, William B. Willcox, and others, eds., The Papers of Benjamin Franklin, New Haven, 1959–, 27 vols. description ends xix, 332n; George DeCou, Burlington: A Provincial Capital: Historical Sketches of Burlington, New Jersey, and Neighborhood [Philadelphia, 1945], 173).

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