PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY
CENTRAL PARK WEST AT 79TH STREET, NEW YORK 24, N.Y.

NUMBER 2257                                                         AUGUST 18, 1966

A Review of the Bug Genus Pelidnocoris Stal
(Heteroptera, Pentatomidae, Discocephalinae)

By Herbert Ruckes¹

In 1867, Stal erected the genus Pelidnocoris but did not assign a species
to it. The following year, Haglund, after examining the Stal material,
described and established the type species as Pelidnocoris stalii. Until the
present time, this species has been the only one in the genus. While
sorting unidentified specimens in the Stockholm collections in 1960, I
was able to segregate three examples of Pelidnocoris, which, while super-
ficially like stalii, were sufficiently different to be considered a new form;
the differences were particularly evident in the male genitalia. More re-
cently (1962), I captured a single female specimen of another species
while in residence on Barro Colorado Island in the Canal Zone, Panama.
This is a much more robust example of the genus than either of the
other two. Currently, therefore, three species should be assigned to
Pelidnocoris.

GENUS PELIDNOCORIS STAL
Pelidnocoris Stal, 1867, p. 501.

Type Species: Pelidnocoris stalii Haglund.

Diagnosis: Head subequal to, or slightly shorter than, median length
of pronotum, longer than wide between eyes; juga overlapping; ante-
ocular processes present; lateral margin of postfrenal lobe of scutellum
not elevated; humeri not spinous.

¹ Research Associate, Department of Entomology, the American Museum of Natural
History; and Professor Emeritus, the City University of New York.

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Generic Characters: Broadly oval, depressed, quite flat beneath,
upper surface somewhat uneven. Head porrect, elongate-oval, subequal
to, or slightly shorter than, median length of pronotum, but longer than
wide between eyes; anteocular processes present, preceded by obtuse,
deep, rounded sinus; lateral margins reflexed, feebly ampliate, apex
moderately broad, with median notch; eyes large, protuberant; ocelli
about two and one-half times as far apart as distant from eyes. Anten-
nae five-segmented, filiform, quite long, reaching onto scutellum to level
where frena end, or beyond; segment I stout, not attaining apex of head,
segment II about two to three times as long as segment I.

Pronotum (figs. 1, 5, 9) somewhat transversely lenticular, at least three
times as wide across greatest diameter as long medially; anterior margin
quite shallowly excavated to receive head and at point of insertion feebly
thickened, sigmoid behind eyes and terminating laterally in an acute,
flat, subspinous denticle directed obliquely anteriorly; anterolateral mar-
gins foliaceous, bisinuate, producing two unequal lobes, larger, posterior
one directed laterally, smaller, anterior one directed obliquely forward;
humeri not produced; disc slightly uneven, with shallow transverse fur-
row behind cicatrices; posterior angles obsolescent. Scutellum linguiform,
reaching apex of abdomen, strongly constricted at area where frena end;
surface uneven, with pair (1 + 1) of low, obtuse humps on basal third
of disc; postfrenal lobe longer than parafrenal portion and more or less
flattened, becoming ampliate, its margins not reflexed, or elevated, apex
truncately rounded, in some cases with vague, median emargination.
Hemelytra reaching end of abdomen, membranes covered by scutellum,
veins simple; costal margin hardly ampliate opposite base of abdomen,
proximal portion shallowly sinuate, reflexed. Gonnexivum widely ex-
posed, apical segmental angles rectilinear and produced, margin of ab-
domen coarsely serrate.

Bucculae low, more or less uniform in height, slightly divergent poste-
riorly, evanescent at base of head; buccular canal relatively wide, shallow.
Rostrum reaching sixth abdominal sternite, or longer, basal segment
attaining procoxae, segment II weakly arcuate, surpassing mesocoxae,
shorter than segments III and IV taken together. Mesosternum mildly
tumid with shallow, narrow, median sulcus; xyphus short, broad, its
apical margin truncate. Metasternum broadly hexagonal, about twice as
wide as long, its surface flat. Metacoxae farther apart from each other
than each is distant from its respective mesocoxa. Metasternal orifice
conspicuous, originating somewhat laterad of acetabula, peritreme ligu-
late, slightly elevated, slightly curved, ending abruptly at least three-
fourths of distance across plate. Legs unevenly dotted and splotched

1966                                         RUCKES: PELIDNOCORIS                                          3

with castaneous spots; dorsal sulci of tibiae rather narrow, deep. Median
abdominal furrow wide, shallow, extending to seventh sternite; anterior
margin of seventh sternite in male produced forward into obtuse arc;
median length of segment only about one and one-half times its mar-
ginal length.

Proctiger in male (figs. 2, 6) depressed, greatly dilated, somewhat tri-
angular in outline, without central flexure, with conspicuous dorsal ostium
through which anal tube extends; parameres small, obscured by proc-
tiger.

Visible plates of female genital valves (figs. 4, 8, 10) two in number,
these feebly inclined, their ventral surfaces facing partially posteriorly;
apical plates obscured by basal plates.

Key to the Species of Pelidnocoris

1. Anteocular processes ligular-spinate, longer than wide, their apices
reaching lateral margin of eyes; pronotum without distinct antehumeral

notch (figs. 1,9) ........................................... 2

Anteocular processes triangular-denticulate, barely longer than wide,
their apices not surpassing middle of eyes; pronotum with distinct

antehumeral notch (fig. 5)..................haglundi, new species

2(1). Species 17.0 mm. in length; apical angle of posterior lobe of pronotal
margin rectilinear to subobtuse (90° to 95°); anterior lobe of pro-
notal margin oval (fig. 9)..................majusculus, new species

Species not more than 15.0 mm. in length; apical angle of posterior
lobe of pronotal margin acute (55° to 60°); anterior lobe of pronotal
margin acutely triangular (fig. 1)..................stalii Haglund

Pelidnocoris stalii Haglund
Figures 1-4

Pelidnocoris sthlii Haglund, 1868, p. 150. Stal, 1872, p. 10. Distant, 1880-
1893, p. 48, pi. 7, fig. 2. Lethierry and Severin, 1893, p. 88. Kirkaldy, 1909,
p. 220.

Diagnosis: Anteocular processes elongate, reaching outer surface of
eyes; apex of posterior lobe of pronotal margin acutely angled; pronotal
margin without antehumeral notch (fig. 1).

The principal specific characters were given by Haglund. To these
should be added the following:

Antennae filiform, finely setose, reaching at least area where frena
end; fuscous to piceous, basal segment pale, with black stripe on inner
and outer surface, joints, a small central annulus on segment IV, and
basal third of segment V pale yellow; segmental ratios: 20/45/55/60/50,
i.e., segment II slightly shorter than segment III.

Basal plates of female genital valves (fig. 4) elongate-trapezoidal,

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feebly convex, apical margins slightly narrowed, converging medially,
external apical angle of each plate subacute; basal and lateral margins
not conspicuously bordered with black, disc with but few black punctures.

Pygofer (figs. 2, 3) stoutly oblong; genital cup widely open; dorsal
border barely produced; lateral apical lobes broadly oblong, dorsal sur-
faces rather flattened, apical margins sinuate, lateral margins evenly ar-
cuate; proctiger greatly dilated, somewhat rhomboidal in form, having
central ostium exposing apical end of anal tube; from ventral aspect
lateral apical lobes divergent, ventral apical margin (fig. 3) conspicuously
V-shaped.

This species averages 13.5 mm. in length; 9.25 mm. in width across
greatest pronotal diameter.

Type Material: Holotype, male; Mexico, no date; deposited in the
Naturhistoriska Riksmuseum, Stockholm.

Distribution: Mexico. Costa Rica. Panama: Chiriqui. Colombia.

Pelidnocoris haglundi, new species
Figures 5-8

Diagnosis: Anteocular processes short, acutely triangular, not surpassing
middle of eyes; apex of posterior lobe of pronotal margin acutely angled;
pronotal margin with distinct antehumeral notch (fig. 5).

Specific Characters: Form broadly oval; color above sordid yellow-
cream, connexivum pale yellow to deep yellow; punctures castaneous to
piceous, somewhat irregularly distributed except on scutellum, those on
hemelytra tending to aggregate in loose clusters; beneath clear pale yel-
low, punctures restricted to propleura and mesopleura, metapleura and
abdomen impunctate; mesosternum, metasternum, spiracles, pseudo-
sutures, and narrow transverse margins of abdominal sutures castaneous
to piceous, narrow bands of abdominal sutures ending abruptly before
reaching lateral margins.

Head unevenly but somewhat densely punctured; anteocular margins
weakly ampliate, juga narrowly overlapping, leaving small apical notch;
anteocular processes stubby, acutely triangular, not surpassing middle
of eyes; ocelli red, with narrow black ring. Antennae finely setose, reach-
ing well beyond area where frena end; basal segment sordid cream-
yellow, with narrow black stripe on inner and outer surfaces, segments
II to V black, apex of segment III and central broad annulus of seg-
ment IV dull red, basal third of segment V pale yellow; segmental ratios:
20/55/50/70/60, i.e., segment II slightly longer than III (in stalii, ratios
are 20/45/55/60/50, i.e., segment II slightly shorter than segment III).

Pronotum three times as wide across greatest diameter as long medially;

1966

RUCKES: PELIDNOCORIS

Figs. 1-4. Pelidnocoris stalii Haglund. 1. Head and pronotum. 2. Pygofer
(dorsal aspect). 3. Pygofer (ventral aspect). 4. Genital valves of female.

Figs. 5-8. Pelidnocoris haglundi, new species. 5. Head and pronotum. 6. Pygofer
(dorsal aspect). 7. Pygofer (ventral aspect). 8. Genital valves of female.

Figs. 9, 10. Pelidnocoris majusculus, new species. 9. Head and pronotum. 10.
Genital valves of female.

transverse furrow behind cicatrices shallow; surface between humeri
rather flat, distinctly transversely rugose; humeri feebly elevated, with

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well-defined notch between them and base of posterior margins of ante-
humeral lobes. Postfrenal lobe of scutellum conspicuously ampliate, apical
margin roundly subtruncate, feebly emarginate centrally; basal two eleva-
tions present but not prominent, saddle between them very shallow;
remaining surface uneven; punctures more uniformly distributed than
elsewhere. Surface of hemelytra slightly uneven, impunctate area feebly
elevated; punctures piceous, tending to accumulate in loose clusters; ex-
ternal apical angle of corium infuscated; membranes very pale brown,
paler basally and apically, veins concolorous, subparallel. Punctures of
connexivum fuscous tending to be most dense on basal half of each
segment.

Rostrum reaching through sixth abdominal sternite; median ab-
dominal furrow infuscated, extending most of distance through disc.

Basal plates of female genital valves (figs. 8) lying more horizontally
than in stain, slightly convex, somewhat trapezoidal, with lateral margins
feebly sinuate, external apical angle of each plate acute, weakly pro-
duced; basal and lateral margins broadly banded with black, disc of
plates with few black punctures.

Pygofer (figs. 6, 7) somewhat elliptical-oval, apical halves of lateral
apical lobes bent inward so that their apices approach each other, inner
surfaces distinctly concave; dorsal border of capsule produced over base
of proctiger, genital cup widely open, elongated; proctiger (dorsal aspect)
almost sagittate, its apex acute and slightly produced posteriorly, dorsal
orifice quite large, somewhat pyriform in outline, end of anal tube clearly
evident; from ventral aspect, lateral apical lobes more or less parallel,
hiatus between them elongate, ventral apical margin between lobes
rather narrow, shallowly U-shaped.

This species averages 12.0 mm. in length; 9.0 mm. in width across
greatest pronotal diameter.

Type Material: Holotype, male; Fonte-boa, Amazonas, Brazil; no
date; ex collection Haglund; deposited in the Naturhistoriska Riks-
museum, Stockholm. Allotype, female; same data as for holotype. Para-
type, female; same data as for holotype, except deposited in the Ameri-
can Museum of Natural History.

Distribution: Brazil: Fonte-boa.

Pelidnocoris majusculus, new species

Figures 9, 10

Diagnosis: Base of postfrenal scutellar lobe with pair (1 + 1) of prom-
inent umbonate elevations; angles of antehumeral pronotal lobes recti-
linear; anterior marginal lobes rounded (fig. 9).

1966                                           RUCKES: PELIDNOCORIS                                            7

Specific Characters: Broadly ovate; above glossy, stramineous to pale
ochraceous, with irregularly distributed, fine, ferruginous and fuscous
punctures; beneath paler, with castaneous to fuscous punctures restricted
to thoracic pleura; mesosternum, median abdominal furrow, margins of
abdominal sutures, pseudosutures, and spiracles castaneous or darker,
the extreme lateral ends of the transverse abdominal lines terminating
in a sagittate mark; metasternum testaceous.

Anteocular processes of head stout, ligulate, their apices reaching
outer surface of eyes; margins before processes feebly ampliate, strongly
reflexed, disc of head concave; apex evenly rounded, with small apical
notch; punctures on juga ferruginous, those on vertex piceous; ocelli
red, less than twice as far apart as distant from eyes. Antennae filiform,
strongly setose, reaching middle of scutellum, stramineous, basal three
segments irregularly dotted and splotched with piceous, basal half of
segment IV and small apical portion of segment V fuscous; segmental
ratios: 37/90/90/90/80, i.e., segments II, III, and IV equal, each slightly
longer than segment V.

Pronotum (fig. 9) three times as wide as long medially, surface some-
what undulant, transverse furrow behind cicatrices quite shallow; punc-
tures irregularly distributed, those near foliaceous lateral borders ferru-
ginous; anterior apical spinous denticles prominent, acute, about as
large as anteocular processes; anterolateral foliaceous lobe somewhat
oval, apical angle of posterior lobe rectilinear, humeri subprominent,
without antehumeral notch. Scutellum reaching end of abdomen, sur-
face quite irregular; basal elevations subconical; elevations on base of
postfrenal lobe umbonate, remaining surface distinctly undulant; lateral
margins of postfrenal lobe parallel, apex broadly, roundly truncate;
punctures ferruginous and castaneous, somewhat irregularly distributed,
densest near margins. Hemelytra unevenly punctured, some punctures
aggregated in loose clusters; membranes reaching end of abdomen, color-
less, veins also colorless. Gonnexivum widely exposed, stramineous with
scattered red and ferruginous punctures; basal half of extreme lateral
margin of each segment fuscous; apical angles of segments rectilinear,
rather weakly produced.

Venter very glossy. Ostiolar peritreme ligulate, gently curved, quite
long, its apex nearly reaching lateral margin of plate. Rostrum reach-
ing onto seventh abdominal sternite. Legs pale yellow, irregularly
spotted and blotched with castaneous spots, terminal tarsal segment
tending to become rosy.

Basal plates of female genital valves (fig. 10) ovate-elliptical, dis-
tinctly longer than wide, convex, their apical halves gradually curved

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dorsally, their surfaces facing posteriorly, their lateral margins feebly
sinuate, their surfaces provided with fuscous punctures on inner and
apical portions, margins not colored.

This species measures 17.0 mm. in length; 10.0 mm. in width across
greatest pronotal diameter.

Type Material: Holotype, female; Barro Colorado Island, Canal
Zone, Panama; June 22, 1962; H. Ruckes, collector; deposited in the
American Museum of Natural History.

LITERATURE CITED

Distant, W. L.

1880-1893. Heteroptera. In Godman, F., and O. Salvin, Biologia Centrali

Americana. London, Heteroptera, vol. 1, 462 pp., 39 pis.
Haglund, C. J. E.

1868. Hemiptera nova. Ent. Zeitg., Stettin, vol. 29, p. 150.

KlRKALDY, G. W.

1909. Catalogue of Hemiptera (Heteroptera). Berlin, vol. 1 (Cimicidae),

392 pp.
Lethierry, L., and G. Severin

1893. Catalogue general des hemipteres. Brussels, vol. 1, 286 pp.
Stal, C.

1867. Bidrag till Hemipterernas systematik. Ofvers. K. Vetensk.-Akad.

Forhandl., vol. 24, pp. 491-560.

1872. Enumeratio cimicinorum Americae. K. Svenska Vetensk.-Acad.
Handl., vol. 10, no. 4, 159 pp.