Article beginning on page 395.
Psyche 7:395-397, 1894.

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Psyche, Vol. 7, 1896,
Plate 9.
COOLEY, - A NEW STRUCTURAL CHARACTER.




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PSYCHE.
A NEW STRUCTURAL CHARACTER IN INSECTS.
BY R. A. Kl01,EY B. S., AMHERST, MASS.
While studying the wings of the Gyp-
sy Moth for androconia I observed a
peculiar strnctt~re which I have nevei
seen definitely described. This strnc-
tux is a small oval patch'of short, sharp spines on the under side of the fore
wing, near the base of the hind margin.
A short notice of this, with illustrations, appears in Part I1 of Prof. C. H. Fer-
nald's Report on the Gypsy Moth, just
published. The spiny area was also
found in Cyambzis lapeatelhis Clem.,
and is described in Prof. Fernald's Mon- op~pli of the Crambiclae, recently pub-
lished in the Thirty-third Annual Re-
port of the Massachusetts Agricultural
College. Further investigation has
revealed the fact that the structure is
not confined to Po~thetria dispar
(Linn.), and Cravzjus laqueatellus
Clem., but is present in very many of
the Heterocera, and that whenever this
occurs, there is always a corresponding
patch on the thorax, at the place where
the spines rest when the wings are in
repose.
The only previous mention of any-
tliii\g of the kind, so far as known to
me, is by Dr. W. Donitz, who in an
article entitled "A Singing Lepidop-
teron," published in 1887 in the Berliner entomologische Zeitschrift, Vol. 31,
states that while holding a male of
DionycJzopics nivcus Men. between his
fingers it made a chirping noise. D.
m'veus is found in Japan and Siberia
and is related to our Spilosoma. He
states that the sound is produced bv the rubbing together of brushes of sharp
chitinized spines, one on the under side of the fore wings near the base, and one on the upper side of the hind wing. Hc
expressed the opinion that the sound is
produced for sexual attraction, but he
was hardly iustiflecl in this conclusion. since he had only males for examina-
tion. Though I have studied many
species I have never found anything
like what Dr. Donitz describes on the
hint! wing, but as previously stated, the second area is always found on the
horax. May it not be that lie was
mistaken in his observations?
The following descriptions were made
from Catocala conciimbens Walk., an
insect which shows the structures clis-
tinctly, and which may he considered
as typical. Figs. I, 2, 3, and 4 of Plate 9. were drawn from this insect. On the
fore wing the at ea Fig. I, s, is more or less oviil in form with its longest axis nearly parallel to the hind margin of
the wing and it is without scales. It
has a definite boundary at which the




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396 PSYCHE. [July 1896
>pines disappear and the scales begin.
The points of the spines are raised at
an angle of about 4.5' and directed
obliquely away from the edge of the
wing. Fig'. 2, is taken from the edge
of the patch on the left wing of Fig. I, and shows both the spines and border-
ing scales in their relative size and posi- tion in relation to the wing. Fig. 3
is a lateral view of the spines as seen
from the edge of a fold through the
spiny area.
On the thorax the area is of similar
form and size, with clearly defined
boundaries and is located on the n~eta-
scutum at the base of the abruptly
raised meso-scntellum. See Fig. I, S,,
;III~ Fig". 4, S,. The area on the thorax is slightly raised and flattened and has no scales. The spines which c.over
this area are precisely like those
on the wing and are so directed as to
point opposite or nearly opposite to
them when the wings are closed. The
spiny area when present occurs in both
sexcs, even on the thorax of the apterous females of the species of Orgyia. In
the microlepicloptera, so far as has
been observed, the spines both on the
wing and thorax are much farther apart
than in the "VLicros.
So far as is known the Rhopalocera
do not possess these structures. There
is, however, on the fore wings of butter- flies a patch of modified scales which
are pointed and elevated, but the patch
is of irregular shape and has no definite boundary. In some it is very apparent
(Anus& $exifpus Linn.) while in
others it is obscure {Pieris r@ae
Linn.). The scales are often smaller
than the general type of scales of the
wing, but they are much larger than
the spines of the Meterocera. There is
no corresponding area on the thorax
but on the hind wing the scales near
the base of the costa are similarly modi- fied. Fig. 5 shows one of the modified
scales from A. plexi'pus and Fig.
a noimal scale fiom the same wing.
Figs. 7 and 8 ale ~espectively the same
from Heodes hyfophlaeas (Bdv.)
In A. flexippzi-s the modified scales
are so directed that those on one wing
cross those on the other at an angle.
If the two detached wings be held in
their natural relative positions the scales of tlic two areas perceptibly interlock. It is possible that these scales assist the wings in making a nnifonn movement.
It is an interesting fact that some, at
least, of the Trichoptera possess similar spiny structures. They are not, how-
ever, so well marked as in tlie Hctero-
cera and in some cases (Leptocerns sp.)
they are very indistinct or absent.
Neuroma styg@s Hag. and ffewonia
semifasciata Say have them well
developed, both on the wings and
thorax. The most important difference
is that in the Trichoptera the spines
gradually change to the ordinary slender spines, which cover the whole remain-
ing surface of the wings and body.
Fig. 8, shows the location of the patch
on the wing of Neuronia and Fig., 10,
shows the spines enlarged. Owing to
a lack of duplicate material in this order, only a few species have been examined.
In the Hymenoptera, I have found




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July 18~6.J PSYCHE. 397
the spiny areas in two species.
h e x
coltttfzba (Linn.), and Uroc~rus cres-
som' Nortont both of which have them
very well developed both on the wings
̤n thorax. The patch on the wings
hears a close resemblance to that of the Heterocera except that the spines are
more blunt. The patch on the thorax
can be seen with the naked eye. See
Fig. I I, s, and Fig. 12.
The question at once arises for what
use are these organs? The theory of
Donitz lhal they are for sexual att~sic- tion seems hardly tenable. In this case
they must necessarily produce a sound,
for they could attract in no other way.
7 7
1 his seems scarcely possible, however,
when wc consider the relative directions in which the spines of the two areas
point when they are in contact. In till
cases the spines of the two areas point
in opposite, or nearly opposite direc-
tions, and an attempt to rasp one surface over the other would result in an intrr- locking of the two as of he teeth of two hostler':? groorningcads, whose hzmdles
are pointed in opposite directions. The
fact that the structures are found in both sexes would also seriously weaken the
theory tht they arc for sexual attraction. 'l.'lie most feasible theory in my opinion is, that they serve to hold the wings in place when at rest, thus allowing- :I
relaxation of the muscles of the wings.
We can conccive how this might be EL
geat convenience to moths which close
the wings over the back. Of co~lrse,
the organs would be of no use to moths
which do not close their wings in this
way, as the Geometrina and Pterop-
horidae. and these do not have them.
It should be staled, however, that they
are not found in all moths which do close the wings; the Sphingidac lack them.
The following is the result of an
extended search through the Heterocera
for these organs. The families are
mentioned in the order in which they
occur in Smith's List. It will be found
that while the majority of moths have
the spiny nrea, some groups, some parts
of groups and some individuals lack
them. Families not mentioned have
not been examined. As previously
stated they are not found in the Sphing- idae, although they were discovered in
every species which was examined of
the Sesiidae. The Agaristidae, Synt-
tomidae, Fyroinoi-pliidae, Ctenuchidae,
Nycteolirlae and Lithosiidae all possess them. Eufhancssa mendica Walk.,
formerly classed with the Lithosiiclae
lacks them; but this species is now
considcrcd by some, at least, to belong
to the Geometrina. The Arctiidae,
Liparidae, Limacodidae have them and
the Notodontidae also with the excep-
tion of A'patelodes torrefacta. S. & A.
The Platyptarygidae and Saturniidae
lack them. Of the Ceratocampidae,
Eacles hperialis (Dru.) and Dryo-
cawpa riibiczinda (Fabr.) lack them,
whilc Anisda senahia S. & A. has
them. The Bomhycidae, Cossidae,
Hepialidae and all the families of the
Noctuina. except the Brepliidae have
thein. As already stated they are not
found in the Gcometrina.* They
- ~
~-- -
*The iac~ tlwt Ilh spiny area does not mcur in Bv&m iqians Moesch., one of the Brephidae, tends to confirm the staieineiit of Meyrick that " Brcpbos is a true member 01 t1,is g"o,,p,'' ~Geon,et, ;,>a)




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398 PSYCHE. IJUI~ ts+
occur in the Pyrausticlac, Pyralidiclae, Phycitidae and Crambiclae. The Ptcro-
phoridae do not have thein.
They are
found in the To~tricidae, Graplioli-
thidae, Tineidae, Plutellidac, Gelechii- dae, Coleophoridae, Lithocolleticlac,
Lyonetiidae. Nepticnlidae and Microp-
terygidiie.
While it is possible that these spiny
areas will not prove of great value in
classification, it is somewhat suggestive when a species as Apatelodes torrefacta
S. & A. lacks them; \vhile they are
present in genera placed on each side.
In such cases they may perhaps aid the
systematist.
The following lists contain an cnu-
meration of the insects which I have
examined for the spiny area, referred
to tlieir families. Numerals indicate
the number of species examined.
Species in idick the spiny areas <,re absent- EXPLANATION OF PLATE 9
Fig. I.
Dorsal view of denuded body of
Catocala ro>icambens. Walk., showing the spin? area on the wing at s, and the corres- ponding area on the thorax at Sr
Fig. 2. Portion enlarged from edge of'
the spin? siren on wing of C. concusnbens. Fig. 3. Side view of the spines as seen
from the edgc of a fold through the spiny are;!. on fore wing of C. concumbeus.
Fig. 4.
Lateral viuw of denuded bod^ bt
C. co~ictmzl-em showin~the spiny area at- S,. Fig. 5. Modified scale from the under
side of the humeral angle of the fore wing of Af/osia- $/exi'fpts (Linn.)
Fig. 6.
Non'n'd.1 scale from neiir the
inid-
die of the under surface of the fore wing of A. firxif-fliis.
Fig. 7. Modififil scale from the under
side of the humeral anzle of the fore winpf Heodes kypophinens (Bdv.)
Fig. 8.
Normal scale from near the mid-
die of the ~inilei- side of the fore wingof H. h~~foj+hio.eas.
Fig. 9. Basal portion of the fore wingnf Ncuronia scmif2sciata Sa?: showing- the
spin? area EIL 3.
Fie to. Spines fi-oxi fore \\ing of N.
S~JJ~<~~.YC<~I~C enlarged.
Fig. 11. ~asal portion of fore wing of
Tremex columba (Linn.), showing spinv Eire;!. at s,
Fiz 112. Spines fimni fore wingof 7'.
colfintba enlarged.
NOTES ON I-SVTTERFLIES.-I havc seen V.
(i-ntio@a lay eggs on whitebirch and :' canoe". liiich Lliis ?c;ir, and as far as 1 know this is a new food plant for the species.
Papili'o fimns is unusually abundant in
Brookline, Mass., tins year. ap well :is ~t Jaffrcy, N. H,, especially around
ash-trees,
where I hive seen many eggs laid in the past few diiys, and Eilmosi without exception on the higher branches of ?oiingtrees.
Caroline G. Soute.




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