74 Wright’s Mathematical Papers. 
ment, will teach us that this diminutive insect, like the’rest of the 
aphides, although they propagate millions, are mere ephemera, in 
point of existence, in the parent state; were the casual vegetation of 
this plant, carefully avoided between the harvesting of the old crop, 
and the seeding of the new, a period, in our climate, of about three 
months; and the latter operation deferred till the commencement of 
frost, the parent swarms would most probably perish. An interval 
fatal to their increase, would, indeed, be the necessary and gratify- 
ing consequence ; and, as no parent insect survives the winter, the 
practice, if universally adopted, might secure the final extinction of 
this variety of the family in our country. Net so with those various 
species which inhabit perennials, whose sustenance cannot be with- 
drawn or suspended; but with the “ Aphis Tritici’” it is unques- 
tionably practicable, if the course be seriously undertaken, and dili- 
gently pursued for a few years, which should be considered a duty, 
that every grower of wheat owes to his neighbor as well as to himself.* 
Arr. I11.—Mathematical Papers; by Exizur Wricut, Esq. 
No. I.—An improvement suggested in field Surveying. 
In the common method of computing the area of a field, a meri- 
dian line is supposed to be drawn at some assumed distance from 
the commencing corner, and the number expressing this distance is 
placed at the head of the column of Meridian Distances. But, if 
this meridian line is made to bisect the first side, the number which 
constitutes the first factor becomes 0, and consequently the first product 
vanishes. Should the lots to be surveyed be allowed at a medium to 
consist of five sides, nearly one sixth part of the labor of computation 
will besaved. This will probably appear to Surveyors who are not 
prepossessed in favor of a previous method, to be an acquisition not to 
be neglected, especially, if in other respects it is equally eligible. The 
improvement is comprehended in the following directions. 
In the field-book make two columns, in the first of which insert 
the points of compass, and the sides of the field as they are sur- 
veyed, together with a description of the boundaries. From a tra- 
* While Dr. Muse’s paper was passing through the press, we are assured that the 
Hessian Fly has heretofore been referred, by writers on Natural History, to the or- 
der Diptera, genus Tipula; and that Blumenbach (Man. of Nat. Hist. by Gore, p. 
224,) calls it Tipula destructor, and refers to the Phil. Jour. of Nat. Sci. 1817, tab. 3. 
We are informed also that Dr. Akerly, of New York, some years since, published 
an able paper on this insect, but the Journal containing it is not at hand.—£d. 
