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Psyche 4:179-183, 1883.

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PSYCHE.
ON THE NERVOUS SYSTEM OF THE HEAD OF THE LARVA OF COR TDAL US CORNUTUS LINN.
BY WILLIAM CHRISTOPHER KRAUSS, ATTICA, N.Y. [With Plate 2.1
[Extract from a thesis in entomology, presented to the Faculty ofthe Cornell university for the Baccalaureate in science.]
The nervous system of the head of the
larva of Corydalus cornufus Linn., con-
sists of -
I. The supra-oesophageal ganglia or
cerebrum, and nerves.
2. The crura cerebri.
3. The sub-oesophageal ganglion or
cerebellum, and nerves.
4. The commissures.
5. Thevagus nerve.
I. THE SUPRA-OESOPHAGEAL GAN-
GLIA, OR CEREBRUM. - The supra-oes-
ophageal ganglia (fig. I. I) are situated in the dorso-cephalad part of the head,
midway between the tips of the labrun1
and the base of. the head. They lie
dorsad of the oesophagus, and immedi-
ately entad of the dorsal body wall, be- ing separated from itonly by thin, deli- cate layers of adipose tissue.
The supra-oesophageal ganglia, the
probable homologs of the vertebrate
cerebrum, differ greatly from the other
ganglia or nerve centres of the body.
They are a compound organ composed
of two distinct ganglia or hemispheres
connected together by a short, thick
commissure on the meson, but are some-
times described as a single ganglion.
These hemispheres are similar in out-
line, having an ovoid appearance. The
lateral ends of the hemispheres taper
into the cerebral nerves. In the two-
year-old larva, the cephalo-caudal diam- eter of the hemispheres is three-fourths of a millimetre, and the
two together
attain the length of two millimetres.
The ventro-latero-cephalad borders of
the cerebrum are developed ventrad,
forming the crura cerebri, which con-
nect it with the sub-oesophageal gan-
glion.
The cephalad extremity of the aorta is
attached to the neurilemmn, at the can-




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180 PSrcffE. [ June~July 1%.
dad border of the supra-oesophageal tinues laterad, and enters the muscles oc ganglia on the meson. The opening of the antenna in the head (fig. 1. 9). At the aorta appears as is shown in the the point of entering the muscles it di- plate, fig. I, 7, the dorsal wall having a vides into several small branches. This
forked opening near the attachment of nerve is probably the motor nerve of the the aorta to the neurileinrna. antenna.
Another small nerve (fig. I.
The sup-oesophageal are 4. c) arises from the antenna1 tract, and supplied by two large tracheae lying extends laterad a distance of two milli- parallel to the oesophagus (fig. IV, 4). metres ; it then divides into two branch- Each trnchea sends three branches to
es.
These branches pass dorsad of the
the ventral side of each hemisphere, antenna1 muscles, and enter the integii- These branches divide and subdivide, ment near the retinas of the eyes. ramifying to all parts of the hemispheres The optic nerves. - The optic trunk
(fig. iv) . The supra-oesophageal gan- of nerves (fig. I. 5) arises from the optic glia are covered with a thin, delicate
tract. This trunk extends laterad fi
curtain-membrane, the neurilemrna. short distance and divides into seven The cerebral nerves. - The cerebral distinct branches, the optic nerves. nerves consist of two trunks of nerves, These branches continue their course which originate from two tracts at the laterad, and are distributed one to each lateral apices of the supra-oesophageal of the seven retinas. It; is an interesting ganglia. The cephalad tract gives rise fact. thiit although there iire seven rct- to the antenna1 nerve, and also a small inas, the external parts of only six integumentary nerve, and may therefore ocelli are developed. The presence of be called the antennal tract. The can- the seventh retina and optic nerve can- dad tract gives rise to the optic nerves, not be doubted, as it was observed in and may therefore be called the optic many specimens of the one- and two- tract. year-old larvae. Fig. vi shows the The aniewKuZ nerve. - The antenna1
separation of the optic trunk into the
nerve (fig. I. 4) arises from the anten- seven optic nerves. The optic ami an- nal tract.
It extends laterad a distance
tenmil nerves are protected by a cover-
of one and one-half mill]metres, and
ing, the extension of the neurilen-iina
divides into a cephalad and a candad or thcca (fig. VY. 3) which covers the branch. sub- and supra-oesophageal ganglia and The cephalad branch (fig. I. 4. a)
IILTVCS.
continues its course laterad, then ceph- 2,
The crwa cerehri. - The cr.ira
dad, and enters the antenna, supplying
ccrebri or the cerebro-cerebellar com-
it with nerves. It is therefore, prob- missures (fig. iv. 3 and fig. ~11. 2) are ably, the tactile or sensor nerve of the two cords of nerve matter connecting antenna. the sub- and supra-oesophageal ganglia, The caisdact branch (fig. I. 4. 6) con- and with them encircle the oesophngus.



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GEAL GAW-
.-The sub-oes-
nding to the cylindrical
es off two nerves, the vagus and the
separated fr
peo-labral (fig. I. 2, 3 and fig. iv. 8, a layer of m ? nerves.-The cly- ganglia.
ypeus, and a fourth, is one millimetre, in the two-year-old extends cephalad to larva. It is connected to the supra-oes-



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182 PSYCHE. [ June-July I-.
oesophageiil ganglion, and continue their cephalad to inesad, give off two branch- course cephalad into the labium. At a es. one from each nerve. These point one millimetre from the ganglion branches continuecephalo-laterad, pierc- two branches are gi\+en off laterad, one ing the floor of the mouth. These
from each nerve, which divide into sev- branches also divide into several smaller end small brandies piercing the integu- br:ttichcs. The arch of the gustatory merit , nerves gives off two small nerves, going At a point two mi!limctres froin the cephalad, which unite at a point one gauglion two branches are given oft", millimetre from the arch. This united one from each nerve, going cephalo-
nerve divides hito three small nerves,
laterad to the integument. One going cephalad, and two going At a point three millimetres from tlie cephalo-laterad. The gustatory nerves gnnglion the liibiiil nerve sepalantes into and branches are very fine and delicate, two large branches, one extending to the and are closely related to the integument palpus, and one to the distiil end of the which forms the walls of the labium iiiid ligula. The nerve of the labiiil palpus lipiii. enters that organ, and near its extrem- The maxillary nerves. - The maxil- ity separates into several small branch- lary nerves (fig. 11. 5 and fig. in) arise CS. The ligiilar nerve continues cephit- from the ventro-latero-cephalad borders lad into the Sigula, and near its extremity of the sub-oesophageal ganglion as a divides into two or three small branches. singti; trunk, which immediately divides The nerve of the labid palpus gives off
into four branches. These may be in-
very small nerve nt the point of enter- dicatcd by thy letters :I, b, c, d, fig. it. ing the palpus, 5, and A, B, c, fig. 111. The gustatory nerves. - The giistn- A (fig. in), which is the tory nerves (fig, 11. 21, if they may he largest of the branches, forks at a point so citlletl, arise from the cephalad border about two millimetres from the gan- of the sub-oesophageal gimgiion, and
glion. Both branches enter the max-
continue their course cep11aSiid into the illn, going to its extremity. and one of ligula, being in close relation to the floor them enters the maxilhry palpus. of the mouth. At a point three 11iilli-
Nerve B, - This branch divides into
metres from the ganglion, at the c;iu(]a(J two branches, three millimetres fro131
part of the lignia, the nerves meet the ganglion, one branch forking im- on the meson, forming an arch. The n;eciiately and going cephaliid. The ilextnil nerve sends a small nerve lateral other branch continues litterad, clivXing ahit one ami one-half niiilimetres from into several brunches which pierce the the ganglion, while the sinistrill nerve iiitegnn-ient. sends ;I branch laterad one millimetre Nerve c.-This branch forks two mil- from the gnnglion. The two nerves, at &metres from the ganglion, one branch - the point of changing their course from going cephdad to the maxilla, the other



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June-July 1884.1 PSYCHE. 183
branch going caudad, giving branches
to the maxillary muscles in the head.
The cephalad branch divides into two
branches four and one-half millimetres
from the ganglion, both continuing their course cephalad.
The fourth nerve (fig. 11. 5. d) is a
very small nerve which divides into two
branches entering the maxillary muscles. The mandibular nerve. - The man-
dibular nerve (fig. 11. 4 and fig. v)
arises from the dorso-latero-cephalad
borders of the sub-oesophageal ganglion, and continues laterad to the mandibles.
Before entering the mandibles three
branches are given off (fig. v. 2, 3, 4). The first branch (fig. v. 2) gives oft'
two nerves which go caudad, entering
the manclibulai- muscles.
The second branch (fig. v. 3) goes
laterad a short distance, then forks. The caudad fork, dividing into two branches, enters the mandibular muscles. The
cephalad branch is united to a long nerve going cephalad.
This nerve forks one
and one-half millimetres from the base
of the mandibles. This nerve extends
caudad of its attachment to nerve 3
(fig. v), and enters a muscle. Just
caudad of its attachment to nerve 3 it
iives off a very fine and delicate nerve which goes cephalad into the mandibles.
Nerve 4 (fig. v) goes laterad two inilli- metres, then forks, one branch going cau- clad to supply the mandibular muscles in the head, the other branch going cepha-
lad into the mandibles.
The mandibular
nerve gives oft' a branch at the point of entering the mandibles, two branches
one and one-fourth millimetres from the
base of the mandibles, and then forks at a point two and one-fourth millimetres
from the base into two branches, which
continue their course cephalad. The
more minute branches of the mandibular
nerve are shown in fig. v.
Other nerves. -A small nerve (fig,
11. 6) arises immediately caudad of the
attachment of the labial nerve on the gan- glion, and divides into several branches going to the adjacent muscles.
From the lateral borders of the sub-
oesophageal ganglion two nerves are
given off, one on each side, going cau-
dad parallel to the commissures (fig. 11. 8). These nerves enter the pel-ivisceral cavity.
At the caudad part of the ligula,
three millimetres from the sub-oesopha-
geal ganglion on the meson, are at-
tached two long nerves going caudad
(fjg. 11. 7). These nerves are joined
to the labial nerves by neurilen~ina
and by two very fine nerves, one on
each side. At the ganglion each nerve
gives off two small, delicate nerves
which are joined to nerve 6 (fig. 11).
The main branch continues caudad, but
no caudal attachment was found. The
cephalad attachment of these nerves is
not shown in fig. 11, having been clis-
sected away to show the cephalacl ex-
tremity of the gustatory nerves.
4. THE COMMISSURES. - The cau-
dad end of the sub-oesophageal ganglion
terminates in two large white cords, the cominissures (fig. 11. 9, fig. VII. 4).
These comrnissures are similar to the
co~nimiss~~res of the body, and join the sub-oesophageal ganglion to the first




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184 PSYCHE. [ June-July 1884.
thoracic.
Each commissure gives off a
nerve three and one-half millimetres
from the ganglion, going caudad. The
distance of these nerves from the gan-
glion varies however (fig. 11. 0).
5.
THE VAGUS NERVE. - The vagus
nerve of CurydaZus curnutus arises as
two nerves from the crura cerebri, dor-
sad of the labial nerves (fig. IV. 9).
These nerves pass cephalo-mesad, fonn-
ing two arches, and unite in a ganglion
on the media& lhe dorsad of the palate.
This ganglion (fig. I. 2, fig. xv. 2) is sometimes called the frontal ganglion,
and is immediately cephalad of the
supra-oesophageal ganglion. The va-
gus nerve departs from the caudad part
of the ganglion, passes caudad between
the aorta and the oesophagus, and con-
tinues on the median line until it reaches a point two millimetres caudad of the
frontal ganglion (fig. IV. 9). Here it
enters another ganglion smaller than the frontal ganglion. This ganglion is also
situated on the median line between the
aorta and the oesophagus. Two nerves
depart from this ganglion, going latero- candad to the sides of the oesophagus
(fig. I. 8, fig. IV. 0). They continue
their course caudad until they reach the pi-o-ventriculus, where they divide into many branches.
The vagus nerve gives branches to the
aorta in the head, and numerous nerves
are continually given off to the oesopha- ' gu s .
SEXUAL CHARACTERS IN THE CHRYSALIDS OF GRAPTA INTERR 0 GA TIONIS.
BY MARY ESTHER MURTFELDT, KIRKWOOD, MO.
The publication in PSYCHE for No-
.
vember-Dccembcr 1883, v. 4, p. 103-
106, of the full text of Mr. Lintner's
interesting paper on "A new sexual
character in the pupae of some lcpido-
ptera," reminds me of an observation
which I made last summer on the chrys-
alids of Grapta interrogationis.
Desirous of obtaining fresh specimens
of this species, I placed about a dozen
elm-feeding larvae in a rearing cage,
from which, in due time, I obtained
eleven chrysalids. These were, in res-
pect to color and ornamentation, of two
distinct sorts. The larger proportion
were of a dull, pale fuscous with darker brown lateral stripes, dots and mark-
ings, without a trace of metallic orna-
mentation, while four were much paler
in general color, inclining to golden
brown, each ornamented with the eight
brilliant, pale-golden, papillose dorsal spots by which this chrysalis is usually characterized. From each of the pale
and gilded chrysalids emerged a female,
while the seven dark iwd unornamented
ones gave forth males exclusively.
This observation may be a mere cor-
roboration of a well known fact con-
cerning the sexual characters of the
species, but if so I have not met with it, or it has entirely escaped my memory.




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Fig. I.
Dorsnl view of the head, showing the supra-oesophageal ganglia and nerves. x 6.
I. Supra-oesophageal ganglia. 2, Frontal ganglion. 3. Clypeo-labi-al nerve. 4, Antennal nerve. ri, Sensor branch. 6, Motor branch. c, Integumentary branch. 5, Optic nerves. 6. Oesophagus. 7, Aorta. 8, Vagus nerve. 9, An- tennal muscles.
Fig. 11.
Ventral view of the head, showing the sub-oesophageal ganglion and nerves. x 6.
I, Sub-oesophageal ganglion. 2, Gustatory nerve. 3, Labial nerve. 4, Man- dibular nerve. 5, Maxillary nerve. 6, 7, 8, Unnamed nerves. 9, Commissure. o, Commissural nerve.
Fig. in. The maxilla with its three large nerves. Nerve d, fig. 11, not shown.
x 7-
Fig. IV.
Ventral aspect of the supra-oesophageal ganglia, the crusa cerebi-i turned cephalad. X 15.
I, Supra-oesophageal ganglia. 2, Frontal ganglion. 3, Crura cerebri. 4, Tracheae. 5, Aorta. 6. Optic nerves. 7, Antennal nerve. 8, Clypeo-labral nerve. 9, Vagus nerve. o, Vagus nerve.
Fig. v. The mandible with its nerves. X 7. Fig. vi.
The separation and dissection of the seven optic nerves. X 10.
I, Optic trunk of nerves. 2, Optic nerve. 3, Neurilemma. Fig. VII.
Showing principally the cross-nerve of the crui-a cerebri, the cephalad extremity of the sub-oesophageal ganglion having been dissected away. )( 12.
I, The sub-oesophageal ganglion. 2, Crura cerebri. 3, Cross nerve. 4, Corn- rnissure.




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Plate 2.




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