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Psyche 5:193-199, 1888.

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April 1S89.J
PSYCHE.
NOTES ON THE EPIPHARYNX, AND THE EPIPHARYNGEAL ORGANS OF TASTE IN MANDIBULATE INSECTS.
BY ALPHEUS SPRING PACKARD., PROVIDENCE, R. I. Reaumur was, so far as we have been
able to ascertain, the first author to de- scribe and figure the epiphar~nx, which
he observed in the honey bee and bum-
ble bee, and calls la langue, remarking
that it closes the opening into the oeso- phagus, and that it is applied against
the pa1ate.l According to Kirby and
Spen~e,~ DeGeer3 described the epiph-
arynx of the wasp : and Latreille4 re-
ferred to it, calling it the sous labre. The name epipharynx was bestowed
upon this organ by Sa~igny,~ who thus
speaks of that of the bees : Ce pharynx
est, a la v6rit6, non-seulement cache par la levre sup&rieure, mais encore exacte- ment rccouvert par un organe par-
tidier que R6aumur a d6jA d6crit.
C'est une sorte d'appendice membran-
eux qui est rep entre les deux branches
des mAchoires. Cette partie ayant pour
base Ie bord sup6rieur du pharynx, peut
prendre le nom di6fi$harynx ou d'6pi-
glosse.
He also describes that of diptera
lRdaumur, Mdmoires pour servir a l'histoire des in- sectes, v. s, 1740, p. 318. pi. 28, figs. 4,7,8,9,10,11 /. 'Kirby and Spence, Intr. to entomology, v. 3, 1823, p. 457-
We Geer, v. 2, 1778-v. 26, fig. 11. M. (Kirby and Spence, pi. xii. fig. 2 K.)
dLatreille, Organization ext6rienre des Insectes, p. 184.
(Quoted from Kirby and Spence.)
bSavigny. Mdmoires sur les animaux sans vertebres. Partie ire, 1816, p. 12.
What Walter6 has lately proved to be
the epipharynx of lepidoptera, was re-
garded by Savigny and all subsequent
writers as the labrum.
The latest account of the function of
this organ is that by Cheshire, who states that the tube made by the maxillae and
labial palpi cannot act as a suction pipe, because it is open above. "This opening
is closed by the front extension of the
epipharynx which closes down to the
maxillae, fitting exactly into the space they leave uncovered, and thus the tube
is completed from their termination to
the oesophagus."
It is singular that this organ is not
mentioned in Burmeister's Manual of
entomology, in Lacordaire7s Introduc-
tion A l'entomology, or by Newport in
his admirable article Insecta in Todd's
Cyclopedia of anatomy.
Neither has Straus-Durckheim referred
to or figured it in his great work on the anatomy of MeZolontha vulga~is.~
In their excellent work on the Cock-
roach, Miall and Denny state that "The
epipharynx, which is a prominent part
6lValter, Alfred, Beitge zur morphologie der schmet- terlinge. Erster thel. Zur morphologie der schrnetter- lingsmundtheile. (Jena. Zelts.,~. 18, 1885, p. 752.) ^Cheshire. Bees and bee-keeping. I. London, 1886, P 93-
Consid6rations gfen&rales sur Panatomie cornparfee des animaux articules, 1828.




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194 fl 2X'HE. [April 18%.
in coleoptera and diptera, is not recog- nizable in orthoptei-a."
(p. 45 .)
I am not aware that any modern
writers have described or referred to the epipharynx of the mandibulate orders of
insects, though I must confess that I
have not made extended search aftel
such references and I would be thankful
for information and references. Al-
though Dr. G. Joseph9 speaks of finding
them on the palate of almost every order of insects, especially plant-feeding forms, we are unable to find any specific refer- erences, his detailed observations being apparently unpublished.
The epipharnyx is so intimately asso-
dated with the elongated labium of
certain diptera, that, with Dr. Dim-
rnock,1å we may, refer to the double
organ as the labmm-epipharynx ; and
where, as in the lepidopterous Mic~o$-
teryx semi$ur$ureZZa, described and
figured by Walter,ll and the $anorfi-
dae12 (ParioQa and Boreas), the la-
bruin seems pieced out with a thin, pale, membranous fold which appears to be-
an extension of the epipl~arynx, build
ing up the dorsal end of the labrum, this term is a convenient one to use.
In the lower orders of ti-uly mandibu-
late insects, from the thysanura to the
coleoptera, excluding those which suck
in liquid food, such as the diptera, lepi- SJoseph, Gust, Zur morphologie des geschmackso- ganes bei inseckten. Amtlicher bericht der 50 verr sammlung deutscher naturforscher u. Artzte in Miin- chen. 1877, p. 227-228.
10Dimmock, George.
The anatomyof the mouth-
parts and of the sucking apparatus of some diptera 1881.
11 Op. cit., fig. 3
1-2 Packard, A. S.
Psyche, 1889, v. 5, p. 159-164.
doptera and hymenoptera, and the me-
captera (Pano7-$idae) with their elon-
gated head and feeble, small mandibles ; the epipharynx forms a simple mem-
branous palatal lining of the clypeus
and labruin.
It is not. so far as we have
observed in any mandibulate insects in
which the mouth parts are free, adapted
for mastication only, the mandibles
being well developed,-in such insects
there is no soft projecting or pendant
portion, fitted to close the throat or to complete a partially tubular an-ange-
knent of the first and second maxillae.
In all the forms, then, described
below, the epipharynx forms simply the
under surface 01- pharyngeal lining of
clypeus and labrum, the surface being
uniformly moderately convex, and corre-
sponding in extent to that of the clypeus and labruin, posteriorly merging into the palatal wall of the pharynx; the arma-
ture of peculiar gathering-hairs soine-
times spreading over its base, being con- tinuous with those lining the month and
beginning of the oesophagus.
The su-
ture separating the labrum from the cly- peus does not involve the epipharynx,
though since certain gustatory fields lie under the front edge of the clypeus, as
well as labrum, we may in describing
them refer to certain fields or groups of cups or pits as occupying a labral or
clypeal region or position.
In our des&iptions we have called at-
tention to the shape of the front edge of the labrum, whether notched or not, and
whether bearing traces of a median su-
ture, on account of the bearing of these parts 011 the question whether the labrum



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represents a first pair of antennae.
The
lack of traces of a suture in the epi-
pharynx corresponding to the labral su-
ture above, suggests that the labrum does not represent a pair of coalesced appen- dages, and that it, with the clypeus, sim- ply forms the solid epidermal roof of the mouth.
The only soft structures seen between
the epipharynx and labrum besides the
nerves of special sense, are the elevator muscles of the labrum and two tracheae,
one on each side.
The structure and armature of the
epipharyngeal surface even, besides the
taste-pits, cups and rods, is unexpectedly varied, the setae assuming very different shapes. There seems to be two primary
forms of setae, (I), the normal forms
which arise from a definite cell, the
setae being a hypertrophied nucleus, as
first shown by Newport, and (z), soft,
flattened, often hooked hairs which are
cylindrical toward the end, but arise
from a broad triangular base, without
any cell-wall, not arising from distinct nuclei. These are like the gathering
hairs (Cheshire) on the bee's and wasp's tongue ; they also line the walls of the pharynx and extend toward the oesopha-
gus. They are the "hooked hairs" of
Will. The first kind or normal setae
are either simply defensive, often guard- ing the sense-cups 01- sensory fields, or they have a nerve extending to them and
are tactile.
It will be seen by the following de-
scriptions that in the thysanusa no tine gustatory cups or pits have been found ; and that immature dermaptei-a are des-
titute of them. On the other hand taste, cups occur on the epipharynx of the lar- vae of longicorn, scarabaeid and bu-
prestid beetles, and they are as abun-
dantly developed in carabid or car-
nivorous beetles as in plant-eating cole- optera. Also, within the limits of a
family like the lociistidae they are less abundant in one of the more general-
ized genera as A7"i$hidizinz, and more nu- merous in a highly specialized genus, as Cyrto/hyUus,
I should say that I have examined the
taste-cups of the honey bee, finding that they agree with Wolff s figures, and that those of insects of the orders described behw are essentially of the same struc-
ture and all seem by situation to be gus- tatory in function.
Order THYSANUR A.
Lepisma sp. from Havana. - The
specimen examined was one of a number
kindly collected for me by the venerable Professor Poey of Havana in his own
house. The labrum is slightly excavated
along the entire margin, but there is no trace of a median suture ; and over the
surface, are scattered long acute hairs, while at the base and over the clypeus
are thickly planted, singular long setae which are hairy beyond the middle, and
are forked at the end.
The epipharynx ends in front in a
broad median lobe somewhat as in For-
ficula, the edge of which bears numer-
ous very short cylindrical rods, whose
presence can only be distinctly made
out by a power of 400 diameters. This
lobe is also covered with an exceedingly



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fine pile consisting of acutely lanceolate hairs arising from a broad, non-nucle-
ated base ; those on the sides, especially in front, being directed towards the mid- dle ofthe epipl~arynx, and much coarser
than those situated farther back.
There is no median furrow, and no
sense-pits, cups or rods, the median
region being clothed with fine hairs.
Machz'Zis va ~iahilis Say. -The shape
of the labrum and epiphai-ynx is very
singular. The labrum is narrower than
long, the front edge slightly excavated, and provided with a row of short, stiff, broad, flat setae, which end in a short
fork. There are no traces of a median
suture.
The epipharynx has 110 separate me-
dian frontal lobe like that of Lejisma,
but the broad edge simply forms the
under surface of the labrum. The edge
is provided with a singular armature of
about four rows of short thick appressed spines, whose ends turn down a little.
so that they appear like four rows of
somewhat polygonal paving stones ; each
has a central nucleus. I can perceive
no setae arising from them. Whether
these singular shortened and curved rods are gustatory, or in any way sensory, 01- whether simply defensive, remains to be
proved ; I could not detect any nerves
leading to them. From each side of
the end of the epipharynx two series, in oblique rows, of somewhat appressed,
rather large, short conical setae, with a nucleus at the end, curve inwards along
the distal third of the epipharynx, and
thence extend parallel to each other to- wards the base of the epipharynx. Of
these conical setae, those in front when examined with a power of 400 diameters
do not appear to bear a bristle, though
there is a nucleus at the end ; but many of those situated farther back bear a long acute bristle. There is no median fur-
row, but the median region is very
finely pilose, the fine hairs becoming
more numerous at the base and extend-
ing along the epipharyngeal lining of
the clypeus. No genuine sense-pits,
cups or rods could be detected.
Order DERMAPTERA.
Forficula sp. from Cordova, Mexico.
-The labrum is rounded in front with
no traces of a median suture.
Epiphai-ynx with a membranous edge
in front, fringed with a dense row of
short fine setae, and just within the edge are two or three rows of
sinuous, slen-
der, blunt setae, of peculiar shape, which may be possibly gustatory. The sur-
face is covered with very fine scale-like setae, and on each side near the base is a region covered by a short dense pile.
The taste-pits are few in number,
there being only about a dozen on each
side in all ; most of them being situated on the anterior half, and a few near the base. The taste-pits are provided each
with a short fine seta, as usual, arising from the centre.
For$czila larva from Florida. -
The front edge of the labruin is entire, rounded, and there are no traces of a
median suture. The front edge of the
epipharynx forms a slight projection or
lobe, about half as wide as the labrum,
which is fringed with fine setae, some




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of which are hair-like, acute, while
others are blunt and curved. The sur-
face in general is covered with the usual fine pile. The median area is bordered
by a pile-covered area, but along this
region no sense-pits, cups, or rods could be detected with a power of 400 diam-
eters ; over the region where they
usually occur were to be seen scattered
conical setae.
Order ORTHOPTERA.
A wingless Blattid from Florida.
-The labi-um is full and rounded on the
front edge, with no indications of a
median suture. The surface of the
epipharynx is finely and densely pilose. There are no sense pits, cups or rods
visible.
Blatta, a large winged species
from Cuba. - Front of the labrum
slightly excavated. The epipharynx is
provided on the front edge with very num- erous short, stout, minute setae, which
are curved downward, and form when
looked at vertically, a pavement-like
mass ; beyond on the extreme edge is a
dense fringe of short slender rod-like
bristles. The surface elsewhere is
finely pilose, the median region not
being bare. On each side of the mid-
dle is a curved row of stiff' defensive
spines; at the distal end of each row is a sensitive field, containing 20 taste-cups on one side and 23 on the other. Near
the front edge of the clypeal region are two more sense-fields, situated on each
side of the median line, there being 35
taste-cups in each field. The taste-cups in this species are rather smaller than
usual.
Spectrum bivi//atum Say.- In a
specimen from Indian River, Fla. the
front edge of the labrum is entire, but
along the middle are traces of a median
suture. The middle region of the
epipharynx, and the epipharyngeal lin-
ing of the clypeus are covered with fine and coarse setae, but there is no bare
space, and no sense-pits are to be de-
tected. (Those that at first appear to
be such are ordinary cells with the setae broken oft'.)
Camnula $eZZztcida Scudd.- The
labrum is notched, but the edge is plain, not bearing any rods or bristles on the
border of the excavation, or elsewhere
on the labral margin. There is a well
defined short median suture in the mid-
dle of the labrum which sends poste-
riorly two forks.
The epipharynx is free from
hairs
along the middle, and near what cor-
responds to the front edge of the cly-
peus, are two sensitive fields, each con- taining about 35 taste-pits. Just in
front under the suture between the cly-
peus and labrum are two similar fields,
each containing from 40 to 42 taste-pits. There are none in front of these.
Xij5hidium brevfpenzis Scudd. 9 -
-The epiphai-ynx is slightly notched at
the end in the middle and the sinus filled with slender setae. The median line
forms a slight furrow, while the surface of the epipharynx in general is covered
with fine rather stiff short setae.
Along each side of the median line
on the anterior half of the epipharynx
are scattered about 30 taste-cups, mostly without, but some bearing rather large
and long setae. At the base is a scat-




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tered group of seven taste-cups on each
'side of the base of the median farrow,
nearly all bearing a bristle, but some
r
'not; all are so isolated from the other true hairs that they are most probably
gustatory. On each side of the region
corresponding to the front edge of the
clypeus is a group of about 30 taste-
cups, only one or two of the outer ones
of which seem to bear a bristle.
Cyrto~7zyZZus. comavus Scudd. -End
of the labrum notched and the sinus
filled in with stiff blunt bristles, this area extended back on the epipharynx ;
there are distinct traces of a median
suture. Along the middle of the epi-
pharynx the spines are absent. The
taste-cups are arranged much as in
Xiphidium, but they are more numer-
ous, as might be expected, this genus
being in general the more specialized.
There are from 50 to 60 taste-cups in
the front region ; behind the middle a
group of 25 on each side, and over an
area corresponding to the base of the
labrum and front edge of the clypeus is
a seikory field with about 70 taste-cups on each side. They are true cups or
beaker-like papillae, some with a fine,
others with a short, stout, conical seta. The katydid is thus provided with about
170 to I 80 taste-cups on its epipharynx. Anab~us simplex Ha1d.-Front edge
of the labrum full, though there are
traces of a median suture. The surface
of the epipharynx is covered with stout
setae. Along the median furrow of the
epipharynx which is bordered with a
delicate pile, are scattered, especially near the base, a few peculiar taste-cups, each bearing a very short conical seta,
which is larger and shorter than usual
the furrow not being pilose. At a point
situated near the anterior edge of the
clypeus the heavy spines towards the
middle graduate into what appear to be
sense-cups.
CeutkofkiLus maculatus (Harris) .-
Labrum slightly excavated. Surface of
the epipharynx finely pilose. Front
edge at the middle forming a highly
specialized pilose area, excavated on the edge, the sinus being broad and shallow
and the edge lined with a hedge-like
row of close-set gustatory rods. A well
marked median furrow, free from hairs
or bristles, and in front is a gxoup, 30 on each side of the median line, of
raised papillae-like taste-cups, a little sh orter and broader than those of Haden- oecus. At the base of the labral region