204 
‘‘The eggs are laid in the long creases or furrows of the upper 
surface of the leaves (i. e., the blade or strap-shaped part) of the 
young wheat plant. While depositing her eggs the insect stands 
with her head towards the point or extremity of the leaf, and at 
various distances between the point and where the leaf joins and 
surrounds the stalk. The number found on a single leaf varies 
from a single egg up to thirty, or even more.” 
Professor Cook says that— 
“The liy very rarely lays more than three eggs at one time with¬ 
out change of position. She more frequently lays two, and gener¬ 
ally but one. In case she lays but one, it takes less than a quarter 
of a minute, and less than a half a minute to lay three, when they 
are all laid without a change of position on the part of the fly. 
After laying she seems to draw in her ovipositor, soOn to extend it 
again, at the same time crowding into it the one, two or three eggs 
that are next to be laid. She then flies to another leaf, alighting 
usually, not always, with head towards the end of the leaf. She 
then appears to wipe the eggs off the jointed ovipositor. She really 
crowds the egg till the end touches the leaf, when, by friction of 
the leaf and adhesion of the egg, the latter is held fast while the 
egg-tube is withdrawn. If the second and third are to be laid she 
repeats the operation, after which she retracts her ovipositor, re¬ 
stocks it, and in a trice is depositing the fatal germs on another 
leaf. I say usually on the upper surface, for occasionally eggs are 
laid on the stalk, and sometimes on the under side of a leaf. I 
have observed that the fly often makes many unsuccessful efforts to 
cause the egg to adhere on the outer surface of the leaf before she 
succeeds. I have seen a fly work thus for two minutes before suc¬ 
cess crowned her efforts. The fly may thus learn by experience 
that it is easier to deposit on the inner or upper face of the blade, 
and so generally choose that surface. We shall see, too, in the 
sequel, that it is better for the prospective maggot that the egg be 
placed on the upper surface. In four to ten days, more or less, as 
the weather is cool or warm, the eggs hatch. (Lecture, p. 7.)” 
Mr. C. V. Piiley describes as follows the process, in the New York 
Tribune: 
“I have very carefully studied the oviposition of the Hessian-fly, 
closely observing the insect in the act on several occasions; and as 
accurate observations on this point are not easily made, I herewith 
transcribe my notes of several years ago: 
‘Eggs deposited in irregular rows in the longitudinal cavities and 
depressions of wheat stalks, between the stalk and sheath when this 
is loose, or on the leaves between the natural ridge or carinae of 
the upper surface, this last being the more common habit. Ordi¬ 
narily, there are from five to ten in a row, but sometimes more. 
Each egg .02 inch long, cylindrical, rounded at each end, soft, 
translucent, and pale orange-red in color. Before hatching, the 
pale sides of the inclosed larva show through the shell. Larva 
hatched in four days; crawls down leaf to base of sheath, which on 
young grain is at croAvn of root. The orange-red color ’is soon lost, 
and the larva becomes pale, translucent and plump, sinking more 
or less into the stalk by the depleting process kept up.' 
