1851 
THE CULTIVATOR. 
323 
face being in direct contact with and pressing against 
the inner surface of the sheath on the one side, and the 
outer surface of the culm upon the other side. It thus 
wholly fills the spot where it lies, and has no space for 
moving in any direction. This worm on the other hand 
does not fill the cavity in which it lies, its cell being 
larger and double the length of the worm. In this re¬ 
spect it differs not only from the Hessian-fly, but also 
from the wheat-midges, but coincides with some of our 
other species of Cecidomyise, the willow gall-fly, for in¬ 
stance, (C. salicis ) which I described in the first 
volume of Dr. Emmons’ Journal of Agriculture and 
Science, page 263. 
3d. Two, three or more of the Hessian-fly larvae and 
pupae are most commonly found-living in direct contact 
with each other, like a litter of pigs in their nest. This 
worm, however, is always alone. Though there are five 
worms in the stalk under examination, each has a cell 
of his own. They occupy, so to speak, different rooms 
in the same house, each individual having a room of his 
own, with no door for his exit or to admit a visit from 
his kinsmen. 
4th. The natural cavity or hollow in the center of the 
straw, is but little crowded upon, and lessened in size by 
the larvae and pupae of the Hessian-fly. But with this 
worm, as appears from the single plant under examina¬ 
tion, for a distance of over half an inch above the joint, 
the culm has been so crowded upon and compressed by the 
swollens heath, that this hollow is entirely obliterated at 
some points and can be but faintly discerned at others. 
5th. The natural texture of the wheat stalk is but 
little altered by the Hessian-fly larvae and pupae. On 
splitting and cutting the stalk, no evident dissimilarity 
appears in its substance, between the diseased and the 
healthy parts. Here, however, the diseased part is of 
a much more solid and wood-like texture than the un¬ 
affected part above it. 
Miss Morris’ Wheat-midge. —The differences now 
stated, show conclusively that this cannot be the Hes¬ 
sian-fly worm. Another insect so closely allied to the 
Hessian-fly as to have been confounded with it, is known 
to exist in this country; and I avail myself of this op¬ 
portunity to make some explanations with respect to it. 
In 1840 and 1841, Miss Margaretta H. Morris, of German¬ 
town, Pa., communicated to the American Philosophical 
Society and to the Philadelphia Academy of Natural 
Sciences, sundry observations which she had made upon 
an insect infesting the wheat crops in her vicinity, which 
insect she deemed to be the Hessian-fly, and pointed out 
what she consequently regarded as errors in the previous 
accounts of this insect. Her observations were exten¬ 
sively noticed in the agricultural journals of the day. In 
my history of the Hessian-fly, prepared for Dr. Em¬ 
mons’ Journal of Agriculture and Science, and repub¬ 
lished in the Transactions of the State Agricultural So¬ 
ciety for 1846, I found myself obliged to ignore the 
statements of Miss Morris, my own observations showing 
me that the previous accounts respecting the habits of 
this insect were unquestionably correct. Miss Morris, 
however, on the appearance of my article, re-affirmed 
that her observations were also authentic, and called 
upon me to say what her insect was, if it was not the 
Hessian-fly. As I had never seen her insect, I of course 
could not say what it was. Annually, in the latter part 
of June, when the wheat is in blossom in this vicinity, 
a small ash-colored fly, a quarter of an inch long to tho 
tips of its wings, appears upon it in swarms. This fly 
is so closely allied to the Garden Hylemyia ( Hylemyia 
hortensis ) of Europe, that I am in doubt whether it is 
really distinct from that species. When recently cap¬ 
tured, and ere it has become at all shrivelled by drying, 
it has a row of oblong black spots along the middle of 
its back, instead of a continuous black stripe, which the 
European species is described as having. This fly had 
been popularly regarded in this vicinity as being the 
wheat-midge which produced the little yellow maggots 
that had for several years committed such appaling havoc 
in all the wheat crops in this section of the country. And 
I could only conjecture that possibly Miss Morris had 
fallen into a similar error, as she lays much stress upon the 
fact that her insect appears abundantly upon the growing 
wheat in the month of June, and describes the female 
as being destitute of fringes to its wings. I was engaged 
in studying out for publication the habits and transfor- 
mations of this fly, that I might incidentally thereto 
make some reply to Miss Morris, when I was much grati- 
field to be released from a task so unpleasant, by ob¬ 
serving in the proceedings of the Academy of Natural 
Science, for August, 1847, a notice from this lady, that 
she had received specimens of the insect which I had 
described, and that it was clearly distinct from the one 
which she had been investigating. In further confirma¬ 
tion of this fact, I may add that Dr. Harris writes me, 
he has received from Miss Morris specimens of her insect, 
which are not sufficiently perfect to enable him to define 
the marks which characterize it, but which show to his sa¬ 
tisfaction that it is a species of Cecidomya different from 
the Hessian.fly. This point being thus definitely settled, 
I may remark that much credit is due to Miss Morris 
for having detected discrepancies and made discoveries 
which none but a close investigator would have been apt 
to notice; and that she should have confounded toge¬ 
ther two insects that are so very similar in their appear¬ 
ance and habits, can detract but little from her reputa¬ 
tion. Mistakes more gross than this have in repeated 
instances been made by the most acute and experienced 
observers. 
Differences between the joint-worm and Miss Morris’ 
wheat-midge. —From the accounts given of her insect 
by Miss Morris, we are forced to conclude that it too, is 
different from the joint-worm of Mr. Rives. She through¬ 
out represents the larvae as inhabiting the center of the 
the straw. We infer from her description that they are 
not imbedded in the parenchyma of the stalk, but are 
wholly within the hollow in its center, and that on mere¬ 
ly splitting the stalk, they are to be observed adhering 
to the surface which is thus exposed to view. They 
moreover occur in all parts of the center of the stalk, 
from the root upwards, to above the last joint. Now 
this location is so widely different from that of the joint- 
worm, and of the larvae of the Hessian-fly, as already 
pointed out above, that we must deem Miss Morris' in¬ 
sect to be different from either. 
Conclusion. —As the result of this examination then, 
we arrive at the conclusion that the insect brought to 
our notice by Mr. Rives, is different from any of those 
