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Bark lice

Emilie Bess and Kevin P. Johnson
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taxon links [up-->]Epipsocetae [up-->]Psocetae [up-->]Homilopsocidea [up-->]Caeciliusetae [up-->]Archipsocetae Monophyly Uncertain[down<--]Psocodea Interpreting the tree
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Containing group: Psocodea


Psocomorpha is the largest suborder of bark lice, containing 24 families and nearly 4000 species. Psocomorphids live on tree bark, foliage, or leaf litter and eat lichens, algae, and fungus. These bark lice are 2-12 mm long, and most have full-length wings, but some have short wings or are wingless. Members of this suborder exhibit a range of interesting behaviors including aggregation in large numbers, sound production by stridulation, sub-sociality, nesting, and web spinning.



(from Yoshizawa 2002)

General Characters

(from Yoshizawa 2002)

Discussion of Phylogenetic Relationships

The monophyly of Psocomorpha is strongly supported by both morphological and molecular data. Yoshizawa (2002) provided a comprehensive morphological analysis of the suborder, including all 24 families and outgroup taxa from suborders Troctomorpha and Trogiomorpha.  He concluded that the suborder is monophyletic, based on the synapomorphic characters listed under Characteristics, and that five infraorders are included in Psocomorpha: Archipsocetae, Caeciliusetae, Epipsocetae, Homilopsocidea, and Psocetae.

Molecular analysis by Johnson & Mockford (2003) and Johnson et al. (2004) of four genes (nuclear ribosomal gene 18S and mitochondrial genes 12S, 16S, and COI) provided strong support for Psocomorpha and for the monophyly of four of Yoshizawa's infraorders, excluding Homilopsocidea.  Analysis of 18S placed Psocomorpha in a sister relationship to "Suborder Troctomorpha" (not monophyletic) and the parasitic lice (Johnson et al. 2004).

Other Names for Psocomorpha


Johnson, K. P. & E. L. Mockford. 2003. Molecular systematics of Psocomorpha (Psocoptera). Systematic Entomology 28: 409-40

Johnson, K. P., K. Yoshizawa, and V. S. Smith. 2004. Multiple origins of parasitism in lice. Proceeding of the Royal Society of London B 271: 1771-1776.

Lienhard, C. and C. N Smithers. 2002. Psocoptera (Insecta) World Catalogue and Bibliography. Muséum d'Histoire Naturelle, Geneva, Switzerland.

Mockford, E. L. 1993. North American Psocoptera (Insecta). Gainesville, Florida: Sandhill Crane Press.

Mockford, E. L. 2005. Order Psocoptera: Psocids. Pp. 341-355 in C. A. Triplehorn and n. F. Johnson (eds.) Borror and DeLong's Introduction to the Study of Insects. Belmont, California: Thomson Publishing.

Smithers, C. N. 1996. Psocoptera. Pp. 1-80, 363-372 (Index) in A. Wells (ed.) Zoological Catalogue of Australia. Vol. 26. Psocoptera, Phthiraptera, Thysanoptera. Melbourne: CSIRO Publishing, Australia.

Yoshizawa, K. 2002. Phylogeny and higher classification of suborder Psocomorpha (Insecta: Psocodea:'Psocoptera'). Zoological Journal of the Linnean Society 136: 371-400.

Yoshizawa, K. 2005. Morphology of Psocomorpha (Psocodea: 'Psocoptera'). Insecta Matsumurana 62: 1-44.

Information on the Internet

Title Illustrations
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Scientific Name Matsumuraiella radiopicta
Location Japan
Specimen Condition Live Specimen
Identified By K. Yoshizawa
Life Cycle Stage adult
View lateral
Size 3mm
Copyright © 2006 Kazunori Yoshizawa
Scientific Name Cerastipsocus venosus
Location Jaffrey, NH
Comments 8/13/2004
Specimen Condition Live Specimen
Behavior aggregation
Life Cycle Stage adult
View dorsal
Copyright © Tom Murray
Scientific Name Mesopsocus unipunctatus
Specimen Condition Live Specimen
Identified By K. Yoshizawa
Sex Female
Life Cycle Stage micropterous adult
View anterolateral
Size 3mm
Copyright © 2006 Kazunori Yoshizawa
About This Page

Emilie Bess
Illinois Natural History Survey, Champaign, Illinois, USA

Kevin P. Johnson
Illinois Natural History Survey, Champaign, Illinois, USA

Correspondence regarding this page should be directed to Emilie Bess at and Kevin P. Johnson at

All Rights Reserved.

Citing this page:

Bess, Emilie and Kevin P. Johnson. 2009. Psocomorpha. Bark lice. Version 25 March 2009 (under construction). http://tolweb.org/Psocomorpha/30218/2009.03.25 in The Tree of Life Web Project, http://tolweb.org/

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