Article beginning on page 233.
Psyche 6:233-235, 1891.

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March 1892.1
PSYCHE.
corn field.
Six days after the bugs com-
menced travelling to the corn, the bugs
covered three feet of every stalk about ten rods into the field. On the seventh day I noticed there were not so many bugs on the stalks. I then noticed that the bugs got less in numbers every day until the tenth day when I could scarcely find a bug on the
stalks. As the bugs were not more than
half grown, it seemed to me a strange act that they left the corn entirely without kill- ing it.
I wondered what became of the bugs and
I turned over some lumps of dirt and out flowed piles of dead bugs and live ones also. By taking close notice I found that the bugs had not left the field but had crawled down in the dirt to die. Half of the bugs were at that time dead. In a few days there came a heavy rain which baked the ground. I have not seen a bug there since."
In making their reports as to the
benefit received from the use of the in- fection, 495 of the 1050 successful ex-
perimenters gave their own estimates of
the number of bushels of grain saved by
the experiment. The sum of these es-
timates amounts in cash value to $89,
I 76.65 or an average of $180.00 for each farmer. It is fair to presume that this
average may be safely applied to the re- mainder of the 1050 successful experi-
ments. This gives an aggregate saving
of $189,000. This amount saved by the
farmers means additional profit for the
railroads and the millers, so that $200, ooo is a very conservative estimate of
the actual value of the experiments in
1891.
CONCERNING THE "BLOOD-TISSUE OF THE 1NSECTA.-11. BY WILLIAM MORTON W HEELER, WORCESTER, MASS. Among the Pterygota oenocytes are
of very general, perhaps universal oc-
currence. Wielowiejski found them in
Rhynchota, Aphaniptera, Coleoptera,
Lepidoptera, Hymenoptera and Diptera.
They had previously been noticed by
Graber in Orthoptera, Coleoptera and
Trichoptera.
I have found them in a
number of orders in which they have
not hitherto been observed and here
subjoin a brief account of my observa-
tions together with a few notes on oeno- cytes in some of the orders in which
they have been studied by others.
ORTHOPTERA. The oenocytes of.
Blatta and Xiphidium are very similar
and may be regarded as typical for this. order. Arising, as above described, by
immigration from the ectoderm just
caudad to the abdominal stigmata, they
remain at their place of origin through- out embryonic life, but later some of the anterior cells wander into the thoracic
cavity. In the adult the metameric ar-
rangement seems to be lost and the
oenocytes lie irregularly scattered along the pleural and sternal walls. The
separate elements never show any ten-




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PSYCHE.
[March 1892.
dency to fuse with one another.
The size of the oenocytes in a given
species appears to vary directly as the
age of the insect. This is shown by the
following measurements :
cytoplasm. nucleus.
Xiph. ensifem
embryo-revolution 7-9 V-
4 completed.
Xi-ph. ensiferzm
hatching 11.
Xiph. ensiferuin
adult. } 37.
Not only do these measurements
show a gradual increase in both cyto-
plasm and nucleus, but they also show
that the cytoplasm grows relatively
somewhat more rapidly than the
nucleus.
EPHEMERIDEA. Fig. 4 represents
the pleural portion of a section through one of the abdominal segments of a
nearly mature Blasturus nymph. Nearly
the whole of that portion of the pleural hypodertnis which is included between
the insertions of the tergosternal, or res- piratory muscles, is seen to consist of
. oenocytes . The hypodermal cells proper , are reduced to small chromophilous
elements filling the interstices between the large clear adenoid cells atid cover- ing them with a thin layer externally.
'That the oenocytes are really still com- pletely imbedded in the hypodermis and
do not protrude freely into the body-
cavity is apparent from an examination
of their inner surfaces, where traces of the inner ends of the hypodermal cells
still persist as plates of protoplasm.
When the abdomen is slit sagittally and
spread out, the pale oenocytes are seen
to line the pleural angles of the segments as an even pavement-like layer. The
area covered by these cells is so large that the metameric masses are interrupted
only by the constrictions separating the segments. In the first abdominal seg-
ment the oenocytes are heaped up into
a mass instead of forming a single layer. It may be further noted that the stig-
matic trunks of the abdominal tracheae
pass into the gills at the posterior edges of their respective segments, so that the oenocyte clusters lie in front of the stig- mata. This is the reverse of their posi- tion in the embryos of Orthoptera, Col-
eoptera and Lepidoptera and were it
not that the insect under consideration
was nearly mature, we might doubt
whether the position of the oenocyte
clusters with respect to the tracheae was of much morphological significance.
On the other hand the oenocytes of
Blasturus certainly show a very embry-
onic condition in that they are still im- bedded when the insect is practically
mature in the hypodermis from which
they differentiated.
The separate oenocytes measure I<
-23. in diameter; their nuclei 7 p..
They are perfectly distinct on the one
hand from the blood corpuscles which
measure only 3.5 P and on the other
from the fat-body.
In the nearly adult nymph of a very
different species (an Ecdyurus-like
form, probably the same as the one fig-
ured in Eaton's monograph PI. 59) the




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March 1892.] Z'LS~TH&?. 235
oenocytes are very similar to those of
the Blasturus nymph. They measure
13- 14.511 - their nuclei I 2 p.. In this species also the difference in size be-
tween the oenocytes and the blood-cor-
puscles is very great. There is nothing
whatever to indicate ?hat the latter
originate from the former.
Very different is the condition of the
oenocytes in the mature nymph of
Hexagenia. Here they may be detected
only with considerable difficulty in the pleural fold between the insertions of
the respiratory muscles as a few scat-
tered cells, differing only in size and
clearness from the hypodermal cells in
which they are imbedded.
ODONATA. In the nymph of an Agri-
onine species of this group oenocytes
were detected after considerable search. They are present in clusters consisting
of a very few small elements (cytoplasm
I 2- r 4 p. ; nucleus 4.5 p.) imbedded, as usual, in that portion of the pleural
hypodermis which is included between
the insertions of the tergo-sternal mus- cles. They seem not to be completely
covered over by the hypodermis but to
project into the body cavity. Their
greater size and pale color distinguish
them from the hypodermal cells.
PLECOPTERA. In a beautiful black
and yellow Perlid larva (perhaps an
Acroneura) the oenocytes are quite as
inconspicuous as they are in the Odo-
nata. The specimens studied in section
were young, measuring only 6 mm,
whereas the mature larva of this same
species measures fully 25 mm. Each of
the metameric clusters consists of from
5-6 cells and these are imbedded in the
hypodermis surrounding the occluded
stigmata. They measure 18.5 p. ; their
oval nuclei 1 I p.. In their affinity for stains they differ but slightly from the hypodermal cells.
The imago of a small unidentified
Perlid presented very different condi-
tions, oenocyte sbeing present in great
numbers and distributed through the
abdomen and thorax. They lie in
niche-like excavations in the hypo-
dermal wall, either singly or in groups. Sometimes they appear to form syncy-
tia. They vary considerably in size
(cytoplasm 14- 55 p. ; nucleus 5-30 ^il) - The nucleus contains a nucleolus-
the only case in which I have found
nucleoli in the oenocytes. Compared
with their homologues in other forms
these cells stain very deeply in borax
carmine.
CORRODENTIA. The bright yellow
oenocytes of Psocus venosus (imago)
are massed in metameric clusters about
the stigmata. The cytoplasm measures
about 18.5 p. in diameter ; the nucleus- 6 p.. They are not imbedded in the,
hypodermis, though they lie in contact
with it.
The fat-body which stains very in-
tensely in Delafield's haematoxylin and
is loaded down with minute urate con-
cretions, extends with hardly any in-
terruption through the whole body -
from the cavity in front of the brain to. the terminal abdominal segments. The
pericardial fat-body is well developed
and very distinct from the fat-body
proper.




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PSYCHE.
[March 1892.
In the workers of Termes flavipes
the oenocytes are much more difficult to detect. They are flattened cells im-
bedded in the pleural hypodermis near
the stigmata. It is their size which
mainly distinguishes them from the hy-
podermal cells ; the latter measuring
only 8 P while the former measure 37 P.
THYSANOPTERA. Oenocytes occur in
compact metameric clusters in a species
of Phloeothrips very common on the
blossoms of Chrysanthemum leucan-
themum during July and August.
These clusters occur in at least six of the abdominal segments, possibly in eight,
but as they diminish in size very rapidly from before backwards, I am not sure
that I have found them in the 7th and
8th metamere&
The clusters lie in the
pleural region well out in the body cav- ity and each consists of some 8 or 10
cells which from mutual pressure are
often very irregular. The cells measure
18.5-26 p in diameter - their nuclei
3-6 P. They are perfectly distinct
from the fat-body and blood corpuscles.
A NEW GENUS AND SPECIES OF TABANIDAE.
BY J. Ma ALDRICH, BROOKINGS, SOUTH DAKOTA. The general appearance of the fly is
that of a particularly fine large silvery Hippoboscid, with brown wings. Nev-
ertheless, an examination shows it to be truly Tabanid in every respect; in fact, I was at some loss for a while to fix
upon a set of generic characters which
would clearly separate it from all the
present genera of Tabanidae. The vena-
tion is normal ; the antennae resemble
Pangonia in shape and number of an-
nulations ; the face is that of Chrysops. 'The upper corner of the eye, making
an angle of about 70 degrees, and not
in the least rounded off at the tip, but rather produced a little in a very fine
point, beyond which is an impressed
line, running to the occiput, is one of
the best characters. The general pro-
portions of the body, .also, are different from those of any other members of the
family known to me.
Its habits are unknown, but from its
appearance the conclusion looks prob-
able that it lives like a Hippoboscid
upon some bird or mammal. Still,
there are no modifications of structure
that give strong support to this theory. Its claws are distinctly larger than those of Tabani of its size. and the large pits at the bases of the hairs on the first and second antenna1 joints seem to indicate
an unusual development of the sense of
touch in this region; both of which
peculiarities are not without weight.
GONIOPS n. gen.
Spurs present on hind tibiae, absent from front ones.
Eyes narrow, terminating above
in an acute angle. Ocelli present. Front broad in female, the callosity longitudinal. .
Proboscis in repose directed forward.
Tho-
rax strongly arched, subglobular. Abdomen (from tip of scutellum) not longer than, and head but about half as wide as, the
thorax.




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