Article beginning on page 368.
Psyche 9:368-369, 1900.

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Cuvqonotus hercr~kanus Latr. var, pictus of one of which there was not sufficient For.
material for determination, but apparent- formicafised L, sz~bpolita Mayr.
ly it is distinct from any species hitherto Lasius nigru.,L.
found in New England.
The collection consisted of 22 species,
THE SO-CALLED MANDIBLES OF SPIDERS.
' BY WILLIAM A. KILEY, ITHACA, N. Y.
Regarding the homologies of the first
pair of appendages of the arachnids
there has always been a question.
According to the prevailing view they
correspond to the mandibles of insects
and are therefore generally referred to
as mandibles. The evidence indicates
that this application of the term is incor- rect.
In 1816 Savigny expressed himself
against any attempt to homologize the
head appendages of the arachnids with
those of insects. He believed that in
arachnids the first pair of appendages,
commonly known as mandibles, in
reality represented a modified pair of
legs.
A little later Latreille, '29, advanced
the view that the so-called mandibles
arc, in fact, the homologues of the sec- ond antennae of Crustacea. He stated
that this is evident from a comparison
with the second antennae of Crustacea
and especially with those of the order
Poccilopodes {Li~~tuZtts, ) As indicative of this homology he introduced the
term chelicerae, (Gr. chelF, claw + keyas, horn), or antemes-/inces,
Following Latreille a number of
prominent zoologists have referred to
the chelicerae as homologous with the
antennae of crustaceans and insects.
Thus, Siebold, '48, says "This view of
Latreille is the correct one, since the
nerves of those organs do not arise from the abdominal ganglia, but directly from the brain, as those of the antennae of
Crustacea and Insecta." ' Ed. Burnett,
54, p. 374. Blackwell, '52, while admit- ting, as highly probable, this homology, proposes as more non-committal the term
fakes instead of Latreille's term chelicerae. While drawing most of their evidence
from the Crustacea these authors have
uniformly spoken of the appendages in
question as corresponding to the anten-
nae of insects. Thus, Simon, '92, p. 29, states that the first antennae of Crustacea are not represented in the arachnids
and insects but that the second antennae find their l~ornologues in the antennae of insects and the chelicerae of arachnids. Those who hold to the view expressed
by Simon have fallen into the error of
assuming the homology of the antennae
of Crustacea and of Hexapoda. But,




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July, 19011 PSYCHE. 369
as Viallanes and others have shown, the
evidence of both cbmparative anatom)
and embryology, clearly indicates that
the antennae of the Hexapoda are the
homologues, not of the second, but of the first antennae or antennules of the
Crustacea. This is evidenced by the
fact that the antennae of insects and the first antennae of Crustacea are inner-
vated by the deutocerebral ganglia while the second antennae of Crustacea are
innervated by the tritocerebral ganglia. The question then is as to whether
Latreille was correct in regarding the
chelicerae as homologous with the second antennae of Crustacea.
The evidence at hand leaves little
doubt as to the correctncss of this view. It is supported not only by comparative
morphology but by pl~ysiological and
embryological data.
Although physiological evidence may
be of doubtful value as a criterion for
determining homology it is interesting
to note that, as pointed out by St. Remy, the first antennae are primarily olfac-
tory organs while the chelicerae, like the second antennae, are primarily tactile
organs.
From the embryological side the most
striking evidence has been the discovery, by several investigators, of evanescent
appendages lying in front of the rudi-
ments of the chelicerae. The most def-
inite account of these vestigeal antennae is that of Jaworowski, '91, who discov-
ered them in the embryos of
Trochosa
sizgmiea.ris.
Latreillc's theory has been assailed by
Balfour, '80, and others on the ground
that the ganglia of the chelicerae are
primitively suboesophageal, like those of the mandibles of insects and that they
only secondarily pass forward to unite
with the supraoesophageal ganglia. This
argument loses weight when we con-
sider the fact that the ganglia of both
pairs of antennae were primitively post- oral in position. Indeed, Pelseneer,
'85, has shown that even in the adult
of Apus, a phyllopod, the second anten-
nae are innervated by suboesophageal
ganglia. Moreover, the studies of Bal-
four antedate the establishment of the
existence, in insects, of- a premandibular segment corresponding to the second
antennae and having its ganglia at first postoral.
A more serious objection has been
urged by Viallanes, '93, who believes
that the chelicerae are the homologues
of the first antennae. Hc states that in the adult arachnids the cerebral seg-
ment innervating the chelicerae has its
commissure entirely preoesoplrageal and
that therefore it cannot be l~omologous
with the tritocerebral or second anten-
nal. As bearing on this argument it
is interesting to note that Janet, 99,
regards the postoesophageal commissure
as a compound of fibers from the three
primitive commissures of the proto-,
deuto-, and tritocerebral ganglia. The
argument of Viallanes can also be met
by the evidence that both pairs of anten- nae were primitively postoral in posi-
tion. If in the crustaceans and insects
the deutoccrebrum has become entirely




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preoesophageal, why may we not have
in arachnids a condition in which even
the tritocerebrum has assumed this posi- tion? Indeed, the acceptance of Jawor-
owski's work as demonstrating the pres-
ence of vestiges of true first antennae
leaves us no other alternative.
The evidence therefore goes to show
that while in the insects the first pair of antennae is retained throughout life, in the arachnids it is the second pair which is represented by the chelicerae. In
both groups the missing pair may be
present in the form of embryonic vestiges. WORKS CITED.
1816. Savigny, J. C. MCmoires sur les
animaux sans vertkbres.
1829. Latreille, P. A. Les crustacds,
les arachnides et les insectes.
1848. von Siebold, C. Th. Lehi-buch
der vergleichenden Anatoinie dcr
wirbellosen Thiere.
185 2. Blackwall, J. Experiments and
observations on the poison of ani-
mals of the order Araneida. Trans.
Linn. Soc. XXI.
1880. Balfour, F. M. Notes on the de
velopment of the Araneina. Quart.
Journ. Micr. Sci. XX.
1885. Pelseneer, P. Observations on
the nervous system of Apus. Quart.
Journ. Micr. Sci. XXV.
1891. Jaworowski, A. Uber die Extre-
mitaten bei den Embryonen der
Arachniden und Insecten. Zool.
Anz. XIV.
1892. Simon, E. Histoire naturelle des
Araignees. I.
1893. Viallanes, H. faudes histologi-
ques et organologiques sur les cen-
tres nerveux et les organes des sens
des animaux articulds. 6e Mdmoire.
Ann. Sci. Nat. Zool. (8) XIV.
1899. Janet, C. Sur les nerfs ce'pha-
liques, les corpora allata et Ie ten-
torium de la fourmi (Myrmica ~utm
L.). Mem. Soc. 2001. France, XII.
GROUP CHARACTERISTICS OF SOME NORTH AMERICAN Burr- TERFLIES - I.
BY SAMUEL H. SCUDDER, CAMBRIDGE, MASS.
Some years since I announced as in
preparation a Student's Manual of North
American Butterflies, north of Mexico,
and a fragment of the same was pub-
ishecl in 1892 (Proc. Amci. Acad. Arts
Sci., XXVII) under the title, The trop-
ical faunal element of 0111 southein Nym- plmlinae systematically treated. Owing
to other demands upon my time progress
upon this Manual has been very slow,
and I am now compelled to abandon the
project. Such few portions as are in
any way complete, mostly written ten
years or more ago, I bring together in
the following series of papers, in the hope that their publication may be of some




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