NEW FINDS OF BAGWORM PTILOCEPHALA BIROI (REBEL, 1909)
FROM VELEBIT IN CROATIA (LEPIDOPTERA: PSYCHIDAE)
Željko Predovnik1, Jurij rekelJ2
1 ob železnici 82, 3313 Polzela, Slovenia. e-mail: predovnik1@gmail.com
2 Struževo 35, 4000 kranj, Slovenia. e-mail: jurij.rekelj@gmail.com
Abstract – We discuss findings of the species Ptilocephala biroi (rebel, 1909) on
visočica mountain in the central part of the velebit mountain range. These are the
first observations of a rare and hitherto little-known species, described in the early
20th century on the basis of only one male specimen. during our field work, we suc-
ceeded in rediscovering the species in nature, where in addition to males we were
successful in observing females, caterpillars and pupae of both sexes. Pupae, female
and caterpillars have not so far been known. data on the biology and the rearing of
larvae are also presented in the paper.
key WordS: lepidoptera, Psychidae, Ptilocephala biroi,  new records, fauna, Croatia
Izvleček – nove nAJdBe vreČkArJA PTILOCEPHALA BIROI (reBel,
1909) nA veleBiTU nA HrvAŠkeM (lePidoPTerA: PSyCHidAe) 
v prispevku obravnavamo najdbe vrste Ptilocephala biroi (rebel, 1909) na gori
visočica v osrednjem delu velebita. To so prva opazovanja redke in do sedaj malo
znane vrste, opisane na začetku 20. stoletja po samo enem primerku samca. Med
terenskim delom smo uspeli ponovno najti vrsto v naravi, kjer smo poleg samcev
uspešno opazovali še samice in gosenice, ter bube z vrečkami obeh spolov. Bube,
samice in gosenice do sedaj niso bile poznane. v prispevku so predstavljeni tudi
podatke o biologiji in gojenju gosenic. 
klJUČne BeSede: lepidoptera, Psychidae, Ptilocephala biroi, nove najdbe, favna,
Hrvaška
Introduction
The genus Ptilocephala rambur, 1858,  has about 24 named species in the
Palaearctic region, especially diverse in the iberian Peninsula and italy (Arnscheid
& Weidlich, 2017). With their winged males and apterous females, they belong to
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the medium-large to large psychids (Arnscheid & Weidlich, 2017). So far, three spe-
cies: P. biroi (rebel, 1909), P. muscella (denis & Schiffermüller, 1775) and P. plu-
mifera (ochsenheimer, 1810), have been reliably confirmed in Croatia (Gumhalter,
2020; Predovnik & kranjčev, unpublished data), while Arnscheid & Weidlich
(2017) mention only P. biroi and  P. plumifera.
on July 28th 1893, the Hungarian entomologist lajos Biró found the first and so
far the only confirmed male specimen of P. biroi in the velebit mountains near
raduc [raduč], about 23 km southeast of Gospić (rebel, 1909). The specimen, now
stored in the national Museum in Budapest, was described as a new species
Oreopsyche biroi by rebel and named after the finder. For now, the species is relia-
bly known only from velebit (Sobczyk, 2011; Arnscheid & Weidlich, 2017).
in the paper we present additional information on the biology and morphology of
P. biroi as observed in the natural environment in Croatia.
Material and methods
Field observations. in the field, we mainly used the method of observing and
photographing larvae and adults in order to obtain data on the behavour of this
species in its natural habitat. Freshly attached female larval cases collected in the
larval habitat were successfully used as pheromone baits for active males. in addition
to observing, larvae, adults, and eggs were collected for rearing and for more detailed
examination.
We used eSri ArcGiS Pro 2.9 software to map all known records from different
localities (Figure 1). For the base map, eSri topographic map layers from the
ArcGiS online version were used (ArcGiS 2021). 
Rearing. The observation colony was established by collecting young larvae in
their habitat. They were kept in mesh breeding boxes in which we made an
approximate copy of the natural habitat with soil, sand, moss and plant particles from
the locality. For food we planted several species of plants, such as: Trifolium
pratense l., Taraxacum officinale Web., Plantago lanceolata l., P. major l. and
various sharp grasses: Brachypodium sp., Sesleria sp., and Festuca pratensis Huds.,
etc. We occasionally added fresh leaves of Rumex sp. and Taraxacum flowers, which
have proven to be a favourite food. The breeding boxes were slightly moistened with
water once a day and twice a day on warm summer days: in the morning and in the
evening. We watered moderately once a week and once every two weeks in winter.
All rearing procedures were carried out in external conditions.
The nomenclature is taken from Arnscheid & Weidlich (2017), the evidence
specimens are preserved in the author's collection, the photographs are the work of
both authors.
Results
Material. Croatia, Srednji velebit, visočica, 1500–1550 m: 1♂ with larval case,
leg. d. Šešok, 20.6.2019, (e.1.–e.p.), coll. Ž. Predovnik. 7♂♂, 9♀♀ with larval
Acta entomologica slovenica, 30 (2), 2022
108
cases, 3 empty old larval cases, leg. Ž. Predovnik, 13.6.2020 (e.l. 14.6.–12.7.2021),
coll. Ž. Predovnik; 19♂♂, 16♀♀ with larval cases, leg. J. rekelj, 13.6.2020 (e.l.
14.6.–12.7.2021), coll. J. rekelj. 13♂♂, leg. Ž. Predovnik, 6.7.2021, coll. Ž.
Predovnik; 4♂♂, 16♀♀ empty larval cases, leg. Ž. Predovnik, 6.7.2021, coll. Ž.
Predovnik; 1♂ with larval case, leg. Ž. Predovnik, 6.7.2021, coll. Ž. Predovnik;
6♂♂, 3♀♀ with larval cases, leg. J. rekelj, 6.7.2021, coll. J. rekelj; 5♂♂ pupa with
larval cases, 9 empty larval cases, leg. J. rekelj, 6.7.2021, coll. J. rekelj. 
Observations. on June 20th in 2019, on one of his mountain trips, Croatian
entomologist damir Šešok found a freshly attached larval case of an indeterminate
bagworm species, below the top of the Mount visočica at an altitude of 1550 m. He
gave the larval case to his friend dr. radovan kranjčev, and a single male hatched a
few days later. dr. kranjčev identified the butterfly as Phalacropterix graslinella
(Boisduval, 1852) and then donated it, together with the larval case to the first
author. redetermination with comparison of the external morphology of the male
corresponds to the description of the species Ptilocephala biroi.
in the following year, on 14th June 2020, we visited the locality on visočica
mountain again. Along the trail just below the ridge, at an altitude of about 1500–
1550 m we found many active young larvae of the genus Ptilocephala sp. The
species inhabits rocky calcareous grasslands (association of Seslerietum juncifoliae)
Æeljko Predovnik, Jurij Rekelj: New finds of bagworm Ptilocephala biroi (Rebel, 1909) from Velebit in Croatia (Lepidoptera: 
109
Fig. 1: distribution map of P. biroi with confirmed and doubtful findings.
on SW and W exposed slopes. larvae were observed mainly on high grass stems,
individually or in scattered groups along the entire grassy slope. The larval cases
were between 5 and 8 mm long. After a few hours of searching, we found three old
cases in the herb layer, hidden among the stones and grasses. despite the sunny
weather, no active adults were observed.
We visited the locality again the following year on 6th July 2021, on the first
warm and sunny day after a short period of rain. The main goal was to find the last
instar larvae and adults. We found many empty as well as several freshly attached
larval cases before pupation, while young larval cases were not present in this year.
We observed that the larvae look for hidden, dry and warm stones for attaching their
cases and are not interested in substrates of vegetation or bare soil. Female cases
were more often attached on exposed sites, attached mostly to the south side of rocks
or larger stones up to half a meter above the ground, as well as under smaller flat
stones. larval cases of males (some already with exuvium) were attached to the
Acta entomologica slovenica, 30 (2), 2022
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Fig. 2: Habitat of
P. biroi on visočica,
Srednji velebit, 1500
m, 6.7.2021. Photo: J.
rekelj.
underside of smaller, mostly flat stones and only exceptionally to the base of larger
rocks. All cases were spun and attached with dense white-silver silk.
At 9:46 am, we observed the first adult male in fast and strong flight low above
the ground vegetation. They are hard to catch because of difficult footing on the
rocky slopes and because males tend to move along rapidly in the wind, so we used
freshly collected female larval cases for pheromone attraction, which proved to be
the most successful way for attracting males. Males appeared at short intervals
throughout the day occasionally saw them fly two or three at a time. A few individual
males flew close to the set females during the day, but none of them tried to mate
with them, from which we concluded that they were probably already fertilized. A
Æeljko Predovnik, Jurij Rekelj: New finds of bagworm Ptilocephala biroi (Rebel, 1909) from Velebit in Croatia (Lepidoptera: 
111
Fig. 3: immature specimens of P. biroi. a. young larva from rearing, 13.5.2021.
Photo: J. rekelj; b. last instar larva from rearing, 20.5.2021. Photo: Ž. Predovnik. 
Fig. 4: a, b. Freshly attached female larval cases, visočica, 1500 m, Photo: Ž.
Predovnik.
crowd of young larvae later in fact hatched from a few of these bags. By 6pm, when
we left the locality, we had counted a total of about 35 active males. 
According to kozhanchikov (1956), relatively large larval cases of P. biroi are
very similar to cases of P. vesubiella (Millière, 1872), which was also confirmed by
our findings and they belong to the “viciella” type in terms of shape (Arnscheid &
Weidlich, 2017). They are rounded, covered transversely with distinctly protruding,
short grass stems, in the final instar larva also covered with dense silk thread. in the
final instars, a pronounced sexual dimorphism is expressed. Male cases are more
pear-shaped, with a distinctive silken tube at the rear-end. The length of male cases
is between 16 and 21 mm and the width is 8 to 11 mm, with a silk tube 4 to 6 mm
long and 3 to 4 mm in diameter (n=19). Female larval cases are cylindrical to
roundish, with a poorly visible thin silken tube and are therefore shorter. The length
is between 9 and 11 mm and the diameter is 12 to 19 mm, with a thin silk tube 2 to
3 mm long (n=11). All measurements apply to larval cases found in the natural
environment. The cases of larvae grown under laboratory conditions are generally
smaller in size, with almost no characteristic dense silk threads.
The wingspan of adult males obtained in nature or hatched from reared material
does not show differences in size and is from 17 to 20 mm (n=21).
Discussion
According to our observation, the last instar larvae and adults P. biroi were found
on visočica every other (odd) year, which indicates a biennial life cycle, with the
appearance of adults in July. The length of daily activity of males that were active
on the day of observation from the morning until late afternoon is surprising. Most
activity is likely to be weather dependent and confined to bright, sunny periods,
which will be clarified by future research.
Acta entomologica slovenica, 30 (2), 2022
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Fig. 5: P. biroi: a. Freshly hatched reared male, 16.6.2020. b. Attached male
larval case with exuvium, visočica, 1500 m, 6.7.2021. Photo: J. rekelj.
Æeljko Predovnik, Jurij Rekelj: New finds of bagworm Ptilocephala biroi (Rebel, 1909) from Velebit in Croatia (Lepidoptera: 
113
Figs. 6–28: Adults and larval cases of P. biroi, collected in natural habitat. 6–17.
Male specimens; 18–22. Male larval cases; 23. young larval case; 24–28. Female
larval cases; Coll. Ž. Predovnik, photo: J. rekelj.
kozhanchikov (1956) states P. biroi also for Bosnia and Herzegovina: »dinaric
Alps, Bosnia, Mt. Travnik«, where in all probability he means the mountainous area
from the settlement of Galica to the mountain peak Paljenik (vlašić) 1933 m above
the town of Travnik. The author does not specify the exact location for the locality
»Herzegovina, Mt. Prenj-Planina«: Prenj is a mountain massif in the south of Bosnia
and Herzegovina, with more than eleven peaks higher than 2000 m. Arnscheid &
Weidlich (2017) mention the unproven finds of Schawerda (1916) from the orjen
mountain range in Herzegovina. These indications suggest that the species may be
more widespread on the tops of the Balkan mountains, since the possible finds
coincide with the distribution of plant communities of high mountain vegetation of
the dinarides.
The rediscovery of the species for the first time in all its developmental stages
allows us thorough morphological and genetic research in the future, a final
comparison of P. biroi with the closely related species P. vesubiella, which is very
similar in external morphology (rebel, 1909; kozhanchikov, 1956; Arnscheid &
Weidlich, 2017).
Acknowledgements
We would like to thank the finder of the first specimen damir Šešok (legrad,
Croatia) and the donor of the specimen dr. radovan kranjčev (koprivnica, Croatia).
We also thank Stanislav Gomboc (kranj, Slovenia) for preparing the distribution
map, reading and commenting on the manuscript.
References
Arnscheid R. W., Weidlich M. 2017: Psychidae. - in: karsholt, o, Mutanen, M. &
M. nuss [edit.]: Microlepidoptera of europe. leiden & Boston (Brill), 8: 1–
423.
Gumhalter D. 2020: Biodiversity, ecological and biogeographical features of
Pyralidae and Crambidae (insecta, lepidoptera) in three Croatian climate
regions. Phd dissertation, University of Zagreb, Zagreb, 369 pp. (in Croatian).
[Prilog 1 – Prvi sistematski popis utvrđenih vrsta iz skupine mikrolepidoptera]. 
Kozhanchikov I.V. 1956: Fauna of the U.S.S.r. lepidoptera. Psychidae.
Zoologicheskii Akademii Nauk SSSR, N.S., 62, 3(2): 1–517.
Rebel H. 1909: eine neue Psychiden-Art aus Croatien. Ann. Mus. Nat. Hungar., 7:
344–346.
Schawerda K. 1916: neunter nachtrag zur lepidopterofauna Bosniens und der
Herzegovina. Vehr. tool. bot.Ges. Wien, 66: 228.
Sobczyk T. 2011: Psychidae (lepidoptera). in: nuss, M. (ed.), World Catalogue of
insects, Apollo books, Stenstrup, 10: 1–467.
received / Prejeto: 10. 3. 2022
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