Article beginning on page 221.
Psyche 8:221-224, 1897.

Full text (searchable PDF)
Durable link: http://psyche.entclub.org/8/8-221.html

The following unprocessed text is extracted from the PDF file, and is likely to be both incomplete and full of errors. Please consult the PDF file for the complete article.

June 1898.1 PSYCHE. 221
head more deeply sinuate at base.
The
plate will give an idea of the more salient features, the figures being drawn by Mr. P. C. Myers and the author. Fig. I is
an outline of the type specimen, a is the mandible, b the maxilla, c the labium
(in which the palpus is shown on one
side only, the paraglossa on the other), d the antenna and e the hind tarsus.
Figs. aa, 2b, and ad represent hitherto
unfigured details of Platydon ZaticoZZe
which are of interest in this connection. It will be noticed that the terminal
antenna1 joint is sinuate or somewhat
ogival at tip. The mandibles are stout-
er than in Stilicus hadzami. The fourth
joint of the maxillary palpi is extremely minute and
scarcely visible except by
careful preparation. The four teeth of
the labrum (fig. 2f) are unequal, the
outer being much smaller than the inner. A nest of JLasitts niger was examined
at Iowa City on May 5th. The galleries
were in and under old logs.
Running
with the ants were seen two individuals
of Myrmobiofa crassicorftis Casey. They
are difficult of detection owing to their habit of keeping close to their hosts and mingling with the moving mass. My
other specimens of this beetle were
taken in August so that this record
points to the probability of hibernation or of a double brood.
During a six weeks' trip to Colorado,
some effort was made to add to the
records of myrmecopl~iles, but the
season was so far advanced that but
little success was achieved. At Colora-
do Springs two species were taken,
which, with their hosts, have been iden- tified by Prof. Jerome Schmitfc. These
were Batrisusfrontalis which was found
in the runways of Lasius cZavigm- be-
neath a log; and Batriszisglobosz~s which occurred in a colony of Camjonotus her-
A STUDY OF THE CATERPILLARS OF NORTH AMERICAN SWALLOWTAIL BUTTERFLIES. - 11.
BY SAMUEL H. SCUDDER, CAMBRIDGE, MASS.
From these statements we see that
there is a somewhat general uniformity
of type in the earliest stage of larval
life among the Papilionini, while there
is an extraordinary diversity in the same caterpillars when full grown. Some
of them alter very much less than
others, some assume the mature aspect
by slow degrees, and others at a start
and at very different periods of life.
Thus maturity may be said to be as-
sumed at the second stage by Laertias
and Iphiclides, at the fourth by Hem-
elides and Papilio, in the course of the fourth stage by Jasoniades, and not
until the final stsge by Euphoeades.
This assumption of maturity consists in
several distinct features which in gen-
eral arc correllated: the form of the
body, the broad features of the coloring



================================================================================

222 PSYCHE. [June 1898.
of the body and the loss of the juvenile armature. In only one instance, Papilio, are the tubercles of the larva retained
(and here only for a single stage) after the adult form and markings have ap-
peared; and, excepting Laertim where
the markings are almost null through
life, Hcraelides is the only example
where the ornamentation of the body of
the adult in any way resembles that of
the newly born caterpillar.
There arc several distinct lines along
which changes have occurred, perrnit-
ting readier comparison between allied
types and to set this forth more clearly the facts are here tabulated, the numerals representing the stages.
From this it would appear to be
tolerably clear that the primaeval catcr- pillar of the Papilionini was covered
with rows of fleshy, mammiforn; tuber-
clcs beset with bristles, and that these were retained through life ; but that in the gradual development of the group
these were lost, first at the final stage as we now find it in Papilio, afterwards at successively earlier and earlier stages ; the loss consisting, first, in the remov- al of the bristles, afterwards in the
lowering of the tubercles until only
smooth and shining lenticles remained,
as now in the full grown caterpillar of
Heraclides ; these again, as in several
genera, were replaced by colored
spots, some of which in caterpillars so
far developed as Euphoeades and Jas-
oniades, assumed special forms.
So when we come to the general
color, it may be fairly presumed that
the early caterpillar was of a dark
color - in no way green as Weisrnann,
from his study of the Sphingidae, seems
to think all young caterpillars were ;
probably of a uniform dark color with
a tendency toward a deepening of the
tint of the region about the third thor- acic segment (which early assumes a
special importance in these caterpil-
. . . . . . .
Tubercles large and bristly
' diminished, often without bristles .
‰ changed to lenticles . . . . . .
. . . . . . .
Lenticles changed to spots
.......
No conspicuous tubercles
Filaments . . . . . . . . . . . . .
. . . .
Body pretty uniformly cylindrical
' slightly tumid in front . . . . . .
' distinctly " " . . . . . . . . .
. . . . . . . .
tapering in front
. . . . . .
Color almost entirely brown
. . . . . .
' dark, saddled with light
'
transversely striped with blackand bright ....... . almost entirely green
. . . . . .
Curving lateral stripe in front
Bright spots in rows on abdominal segments . . . . . . . . . .
A thoracic ocellus
Special markings on first abdominal segment



================================================================================

June 1898.1
PSYCHE.
lars) , and also about the seventh abdom- inal segment, by the tendency of both
markings and dermal appendages to
assume a polar arrangement in clong-
ated forms. By this means arose
through the intensification of these
contrasts the lightening of the middle
parts of the body to form a saddle-
shaped, whitish patch - a marking
surely of great antiquity in swallow-
tail caterpillars, since it is now found at birth in four of our six genera, and a fifth shows a tendency toward it.
This
style of marking has been retained
throughout life in Heraclides only of
all the members of our fauna ; and as it it is in just this genus alone that the
lenticle-traces ot the tubercles persist to maturity, we have certainly in Hera-
elides the perpetuation of a very anti-
quated type.
That in Papilio we have also a very
persistent type may he judged from the
great stability of the upper tubercles.
which are even not lost until after the
assumption of the changed livery of
maturity,- a livery which owes a part
of its variety and enliveument to ex-
change of some of these tubercles for
bright colored spots; these break up
the transverse black stripes in a vari-
able degree, and the stripes themselves
appear to be but little more than reten- tion of parts of the original color (fixed at the particular spots they occupy by
the central position of the black tuber- cles) when the green lively of adult
life is assumed. For it seems to be a
green resembling the green of t11c
leaves upon which the caterpillar lives, that is the ultimate aim of most Papili- onid coloration.
In caterpillars of their
size other colors would be too conspic-
uous tor their advantage, and varia-
tion in this dircction would be natural. Moreover, it is the color reached or
partly reached, in several different ways, as the development of the other types
show; thus in the other striped cater-
pillar, Iphiclides, the stripes grow
obsolescent toward maturity and leave
the caterpillar more completely green.
We may then trace beveral lines, to
a certain extent parallel, along which
the modification of the caterpillars of
Papilionini lifts developed, parallel at least in that the loss of the juvenile
l~sistles has bee11 universal but at rtiEer- ent stages; also that the loss of the
juvenile tubercles has been universal
though not always complete, their loss
being generally made good by lenticles
and these by spots ; and sometime"; by
acceleration, a pllyletic stage is set
further and further back and finally,
perhaps, CI owdecl out.
One of these lines, veiy distinct from
the others, is found in Laertias, which
has developed to so high a degree that
its juvenile bristles, themselves exccp- tionally simple, are completely lost
with the earliest stage; so, too, most
of the tubercles ; but here a very curious change occurs: those which are lost
are replaced in new positions by others
entirely different, which take on a more elongated form and become more prop-
erly fleshy filaments ; while those which remain assume also the new clevelop-
mcnt. The dark and almost uniform
color of the larva throughout life is to be explained probably by acceleration ;




================================================================================

224 PSYCHE. [June 1898.
it is the mature color thrust back into
the juvenile stage, to the obliteration of any trace of the saddle which once may
have prevailed there ; and is in keeping with the present almost complete
assumption of the mature characters at
the second larval stage. In support of
this position I would point out that
traces of the saddle still exist in the
mature forms of other filamentous cat-
erpillars of Papilionini allied to Laer- tias, - Ornithoptera, Menelaides, etc.,
indicating a still larger development of the same in the earlier stages of the
types with which, unfortunately, we
are not yet acquainted. In Laertias,
then, the saddle has been crowded
back out of existence.
Another line of nearly as high devel-
opment wc find in Iphiclides, where
the extraordinary bristles and tubercles are lost with the very first stage and
maturity marks the second. Here
again- no saddle appears, the only trace of it left being in the slight deepening of the color in the new-born caterpillar near the extremities of the body ; here
I conceive that the phyletic stage
marked by the saddle and formerly
developed in later stages from the in-
cipient contrasts of the first, has been pushed back without invading the first
until it is entirely skipped.
A third line is represented by the
remaining genera in which the saddle
is definitely formed and becomes a
marked feature of the earliest stages, to be lost only at a comparatively late
period of life, - in one instance, Hera- elides, not at all. Its loss, however, is effected in two very different methods,
as already pointed out, in Papilio and
in the other genera, indicating lines
along which future strikingly different
processes may go on with widely differ-
ent results ; - in curious contrast to the somewhat similar results following
quite different lines which we see in
Iphiclides and Papilio. In Eupho-
eades and Jasoniades we see also the
development of special and complicated
markings from the simple spots which
have replaced the tubercles ; traces of
the same may be seen in Heraclides.
This review has but imperfectly
shown what curious and striking dis-
tinctions in form and coloring are pos-
sible, distinctions which indicate within the history of single lives the immense
phyletic changes that have occurred
within the group. These changes are
far greater both in structure and in
design than can be proved to have
occurred in other phyletic types among
butterflies, to which have been univer-
sally accorded by the most conservative
of systematists the rank of genera.
Shall we refuse to recognize and so
consign to oblivion the more interesting, more important and more obvious dif-
ferences which here obtain by classing
all the forms under one, wide-reaching
generic name? It were a veritable
travesty of Nature.
Fig. I. Laertias philenor,
2. Iphiclides ajax.
3. Jasoniades glaucus (After Gruber).
4. Euphoeades troilus.
5. Heraclides cresphontes.
6. Papilio astyanax.




================================================================================