The Hessian Fly, and its Parasites. 155 
the 4th of June, 1834, he obtained similar pupee from a wheat 
field near Naples.—About the period of Mr. Dana’s investigations 
in the south of Europe, attention was turned to the injury 
caused by certain larvee among the wheat in Hungary. It ap- 
pears now to be commonly believed, that their parent insect is 
either our Hessian fly, or an animal very closely allied to it. 
{ have searched in vain for any traces of the Hessian fly in 
this country before the Revolution. The Rev. Jared Eliot, in 
his “ Hssays upon Field Husbandry in New England,” Boston, 
1760, treats of the culture of wheat, but makes no allusion to 
any insect having habits like those of the Hessian fly ; neither 
does Kalm, the naturalist, who travelled in this country about 
1750. [am therefore inclined to consider the common opinion 
of the origin of the insect quite as probable as any other which 
has been advanced. Ps 
In this part of our country, wheat is usually sown about the 
first of September. Soon after the plants are up, the Hessian fly 
begins to lay her eggs upon them, and continues her operations 
for several weeks. She deposits her eggs on the upper surface of 
the leaf (i.e. the ligula, or strap-shaped portion of the leaf) of 
the plant. The number ona single k 
saf is often twenty or thirty, 
and sometimes much greater. In these cases many of the larve 
must perish. The egg is about a fiftieth of an inch long, and 
four hundredths of an inch in diameter, cylindrical, translucent, 
andof a pale red color. In about four days the egg hatches; the 
young larva creeps down the leaf, enters the sheath, and with 
the head downwards, fastens upon the tender culm or stalk, gen- 
erally just above some joint. The larva appears to feed solely 
on the sap of the plant; it does not gnaw the stalk, and never 
enters it, but is gradually imbedded in it as the plant matures. 
Having taken its post, the larva is stationary ; 1t gradually loses its 
reddish color, becomes translucent, and clouded with white spots, 
and when near maturity, the central part within is of a greenish 
hue. In about five or six weeks, (or longer if the season is cold, ) 
the larva begins to assume a brownish tinge, and soon is of a 
bright chestnut color, when the insect may be said to have reached 
the state of pupa. It has then some resemblance to a flax-seed. 
The outer skin of the larva becomes the puparium of the pues 
The wheat plant is injured by the loss of sap, but principally by 
the pressure of the larvee and pupe upon the culm. A single 
¥ 
