Proculus mniszechi, copyright Oliver Keller.

Belongs within: Scarabaeoidea.
Contains: Aulacocyclus, Passalini.

The Passalidae, bess beetles, are a group of elongate, flat-bodied scarabaeoid beetles that live in subsocial groups in rotting logs (Schuster 2002). Adults feed on rotting wood and prepare food for the associated larvae (Britton 1970). In members of the subfamily Passalinae, the procoxae do not project much below the prosternum, and the head usually bears paired tubercles. The Indo-Australian Aulacocyclinae have the intercoxal process of the prosternum concealed by the fore coxae.

Characters (from Schuster 2002): Length 20–43 mm. Shape elongate-cylindrical and  depressed.  Colour black (tenerals orange to deep maroon); ventral surface with or without erect, moderately dense, yellow setae. Head  prognathous, narrower than thorax, often with dorsomedian horn. Antennae with ten antennomeres including a three-segmented club that is not opposable and not geniculate (but is capable of being rolled together); club antennomeres tomentose; antennae inserted under a prominent frontal margin. Eyes divided in half by canthus, with exocone ommatidium. Clypeus reduced, separated from frons by suture, or vertical and hidden beneath frons. Labrum distinct, prominent, projecting beyond apex of front of head, clypeal apex deeply emarginate, bisinuate, or truncate. Mandibles projecting beyond apex of labrum, large, curved, toothed, blunt. Maxillae with four-segmented palpi; galea with apical hook; submentum large, prominent; mentum large, emarginate at apex; labium with three-segmented palpi. Pronotum broader than head, quadrate, surface smooth with median, longitudinal groove. Elytra elongate, sides parallel, apices rounded, with striae well developed. Pygidium concealed by elytra. Scutellum triangular, small (exposed only in groove between pronotum and elytra). Legs with transverse coxae, mesocoxae closed; protibiae with several external teeth on outer margin, apex with one spur;  meso- and metatibiae with ridges, apices with two spurs; tarsal formula 5-5-5; claws equal in size, simple; empodium present, not extending beyond fifth tarsomere, with two setae. Abdomen with five visible sternites; seven functional abdominal spiracles situated in pleural membrane. Wings well developed without M-Cu loop, with one apical detached vein. Male genitalia trilobed. Female genitalia with paraprocts, proctiger, and styli absent; valvifers and coxite present. Larvae elongate, subcylindrical, slightly curved (not C-shaped). Colour creamy white or blue-white (except at caudal end which may be darkened by accumulated faeces). Cranium lightly sclerotised. Antennae two-segmented with protruding fleshy base, short. Lateral ocelli lacking. Frontoclypeal suture distinct. Labrum rounded, setiferous at apex; maxilla with galea and lacinia distinctly separate, stridulatory area present, palpi two-segmented (apparently three-segmented). Abdominal segments without annuli. Spiracles cribriform with C-shaped peritremes. Venter of last abdominal segment with two anal lobes. Pro- and mesothoracic legs four-segmented, with long, curved claw; metathoracic leg unsegmented, reduced to a stub with several apical teeth that rub against stridulatory area on coxa of mesothoracic leg.

<==Passalidae [Passalides]
| |--AulacocyclusBB16
| `--CeracupiniBB16
| i. s.: Plesthenus quadricornisMas86
| Eriocnemis lottiniiMas86
| Austropassalus Mjöberg 1917 [incl. Notocetius Hincks & Dibb 1935]CW92
| `--*A. hultgreni Mjöberg 1917 [incl. *Notocetius cornutus Hincks & Dibb 1935]CW92
| Protomocoelus Zang 1905 [=Pelops Kaup 1871 nec Gistl 1834 nec Koch 1836]CW92
| |--*P. australis (Boisduval 1835) [=Passalus australis, *Pelops australis]CW92
| `--‘Pelops’ gestroiMac86
| Analaches Kuwert 1891CW92
| |--*A. puberilis Kuwert 1891CW92
| `--A. australiensis (Stoliczka 1873) [=Cetejus australiensis]CW92
| Labienus Kaup 1871CW92
| |--*L. ptox (Kaup 1871) [=Eriocnemis ptox]CW92
| `--L. inaequalis Gravely 1918 [incl. L. trigonophorus proximus Hincks 1933]CW92
| Gonatas Kaup 1871CW92
| |--*G. naviculator (Percheron 1844) [=Passalus naviculator]CW92
| |--G. germari (Kaup 1868) [=Aceraius germari]CW92
| |--G. minimus Kuwert 1891CW92
| |--G. pumilio (Kaup 1868) [=Aceraius pumilio]CW92
| `--G. schellongi Kuwert 1891 [incl. G. albertisi Kuwert 1891]CW92
| Pharochilus Kaup 1868CW92
| |--*P. dilatatus (Dalman 1817) (see below for synonymy)CW92
| |--P. nitidulus (Macleay 1871) [=Mastochilus nitidulus]CW92
| |--P. puncticollis (Macleay 1871) [=Mastochilus puncticollis]CW92
| |--P. punctiger (Gravely 1918) [=Mastochilus (Pharochilus) punctiger]CW92
| |--P. rugiceps (Hope & Westwood 1845)CW92 (see below for synonymy)
| `--P. scutellonotus Kuwert 1898 [incl. P. pararius Kuwert 1898]CW92
| Mastachilus Kaup 1868 [=Mastochilus Kaup 1868; incl. Episphenoides Kuwert 1891]CW92
| |--*M. polyphyllus (Macleay 1826)CW92 (see below for synonymy)
| |--M. australasicus (Percheron 1841) (see below for synonymy)CW92
| |--M. dilatatus [incl. M. chevrolati, M. crenistrius Boisd. 1835]Mas86
| |--M. lottinii (Boisduval 1835) [=Passalus lottinii]CW92
| |--M. parvifrons (Kuwert 1891) [=Episphenoides parvifrons]CW92
| |--M. politusMas86
| |--M. quaestionis (Kuwert 1891) (see below for synonymy)CW92
| `--M. rigiceps Hope 1845Mas86
|--Didimus [Solenocyclini]BB16
| `--D. ealaensisBB16
|--Serrulus [Macrolinini]BB16
| `--S. sinicusBB16
|--Leptaulax Kaup 1868CW92 [Leptaulacinae, LeptaulaciniBB16]
| |--*L. dentatus (Fabricius 1792)CW92 [=Passalus dentatusCW92; incl. L. quadridentatus Sturm 1826Mac86]
| |--L. bicolor (Fabricius 1801) [=Passalus bicolor]CW92
| `--L. timoriensisMas86
|--Odontotaenius Kuwert 1896S02
| |--O. disjunctusS02
| `--O. floridanusS02
|--P. burmeisteriB14
|--P. goryi (Melly 1833)B14
|--P. jicaqueiB14
|--P. mniszechiB14
|--P. opacipennisB14
`--P. opacusB14

Passalidae incertae sedis:
Popilius disjunctusA-B91
Vellejus compergusMac86
Laches comptonii Kaup 1868Mac86
|--B. indicusJ73
`--B. neelgherriensisJ73
Pleurarius brachyphyllusJ73
Epiphanus Kaup 1871FS90
`--E. abortivus Perch. 1835FS90
Neleus Kaup 1869FS90
`--N. unicornis Serv. 1825 [incl. N. occipitalis Esch. 1829, N. suturalis]FS90
|--O. emarginatusLC40
`--O. tridens Wied in Laporte de Castelnau 1840LC40
|--P. crenulatusLC40
`--P. pentaphyllusLC40

Mastachilus australasicus (Percheron 1841) [=Passalus australasicus, *Episphenoides australasicus; incl. E. distans Kuwert 1898, Mastachilus macleayi Kaup 1868, E. mulleri Kuwert 1891, E. perinvitus Kuwert 1891]CW92

*Mastachilus polyphyllus (Macleay 1826)CW92 [=Passalus polyphyllusCW92; incl. Mastochilus abdominipunctatus Kuwert 1898CW92, P. hexaphyllus Boisduval 1835CW92, P. impressicollis Boheman 1858CW92, Mastochilus impressicollisMas86, P. sexdentatus Eschscholtz 1829CW92]

Mastachilus quaestionis (Kuwert 1891) [=Episphenoides quaestionis; incl. Mastochilus capitalis Blackburn 1900]CW92

*Pharochilus dilatatus (Dalman 1817) [=Passalus dilatatus; incl. Tiberius caffer Kuwert 1891, Pa. cancrus Percheron 1844, Pa. chevrolati Percheron 1835, Pa. crenistrius Boisduval 1835]CW92

Pharochilus rugiceps (Hope & Westwood 1845)CW92 [=Passalus rugicepsCW92; incl. Ph. bilineatopunctatus Kuwert 1891CW92, Ph. brevidentatus Kuwert 1898CW92, Ph. compar Kuwert 1898CW92, Passalus dilatatus Percheron 1835 non Dalman 1817CW92, Ph. politus languidilabris Kuwert 1891CW92, Pa. politus Burmeister 1847CW92, Ph. politusB70]

*Type species of generic name indicated


[A-B91] Athias-Binche, F. 1991. Ecology and evolution of phoresy in mites. In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 1 pp. 27–41. SPB Academic Publishing: The Hague.

[BB16] Boucher, S., M. Bai, B. Wang, W. Zhang & X. Yang. 2016. Passalopalpidae, a new family from the Cretaceous Burmese amber, as the possible sister group of Passalidae Leach (Coleoptera: Scarabaeoidea). Cretaceous Research 64: 67–78.

[B70] Britton, E. B. 1970. Coleoptera (beetles). In: CSIRO. The Insects of Australia: A textbook for students and research workers pp. 495–621. Melbourne University Press.

[CW92] Cassis, G., & T. A. Weir. 1992. Passalidae. In: Houston, W. W. K. (ed.) Zoological Catalogue of Australia vol. 9. Coleoptera: Scarabaeoidea pp. 20–29. AGPS Press: Canberra.

[FS90] Fleutiaux, E., & A. Sallé. 1890. Liste des coléoptères de la Guadeloupe et descriptions d’espèces nouvelles. Annales de la Société Entomologique de France, 6e série 9: 351–484.

[J73] Joseph, A. 1973. Studies on some passalids (Coleoptera) of Kerala—II. Biology and bionomics of Basilianus indicus Kuwert and B. neelgherriensis Perch. Journal of the Bombay Natural History Society 69 (3): 672–676.

[LC40] Laporte de Castelnau, F. 1840. Histoire Naturelle des Insectes Coléoptères vol. 2. P. Duménil: Paris.

[Mac86] Macleay, W. 1886. The insects of the Fly River, New Guinea, “Coleoptera”. Proceedings of the Linnean Society of New South Wales, series 2, 1 (1): 136–157.

[Mas86] Masters, G. 1886. Catalogue of the described Coleoptera of Australia. Part III. Proceedings of the Linnean Society of New South Wales, series 2, 1 (1): 21–126.

[S02] Schuster, J. C. 2002. Passalidae Leach 1815. In: Arnett, R. H., Jr, M. C. Thomas, P. E. Skelley & J. H. Frank (eds) American Beetles vol. 2. Polyphaga: Scarabaeoidea through Curculionoidea pp. 12–14. CRC Press.

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