On the Hessian Fly. 73 
Whether the insects are viviparous or oviparous, I could not satis- 
fy myself; and it is not essential to any useful purpose, as the larve 
in a few hours from their deposit, make their escape from the pel- 
licle in which they were glued down to the leaf, or stalk; and 
crawl down immediately to the nearest joint, where they fix their 
proboscis in the plant; suck, and grow rapidly in a warm tempera- 
ture, and remain in the same position, assuming the chrysalis in 
a few weeks: from which state, the early deposits, in a warm sea- 
son are speedily released; but the chrysalids, from a latter deposit, 
continue in their shells, through the winter, and are not developed 
until the spring, when the approaching heat soon brings them into 
parent existence, to make their new deposits, which latter by the 
10th or 15th of May, make a woful demonstration of their rapid 
growth and progress, by the decline of the wheat plant, upon which 
they had been operating; having then passed through the larva into 
the chrysalis, the shell of which is hard, and pressing upon the tender 
shoot interrupts the ascent of the sap, they thus mechanically affect 
the health and life of the plant, more than by the quantity they had 
consumed by absorption. 
The number of these insects obtained from my small sod, of a 
few inches only, of wheat, is incalculable and incredible, and fur- 
nishes grounds to affirm, that the stack yard, from which it was taken, 
containing several square perches of this nidus, and nutriment for 
them, had 1 not soon after the discovery scraped off and burnt the 
offal, was sufficient to have produced myriads of swarms, to the inev- 
itable destruction of my own, and my neighbors’ crops. 
This fact, then, should teach the agriculturist, the necessity of pre- 
serving their stack yards, and other places, clean, and free from veg- 
etating scattered wheat; and clearly establishes one great source of 
this evil, or rather of the perpetuation and increase of the insect, 
which has excited universal astonishment and dismay, throughout our 
wheat growing district. 
Another source may be found, in the practice, also otherwise rep- 
rehensible, of fallowing for a second successive crop, upon wheat 
stubble ; much scattered wheat thus prematurely vegetated, affords 
sustenance and security to these insects, which might have conside- 
rably perished, at the crisis when this operation is generally per- 
formed, from the absence of a continuous medium of perpetuation. 
The peculiar and, I believe, exclusive prey of this insect is the 
green leaf and stalk of wheat ; analogy, independent of my experi- 
Vou. XX{L—No. 1. 10 
