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Emilie Bess and Kevin P. Johnson taxon links [up-->]Antilachesilla [up-->]Zangilachesilla [up-->]Anomopsocus [up-->]Graphocaecilius [up-->]Cyclolachesillinae [up-->]Hemicaecilius [up-->]Mesolachesilla [up-->]Prolachesilla [up-->]Tricholachesilla [up-->]Dicrolachesillus [up-->]Homoeolachesilla [up-->]Eolachesillini [up-->]Nadleria [up-->]Nanolachesilla [up-->]Lachesilla [up-->]Notolachesilla [up-->]Zonolachesillus [up-->]Ceratolachesillus Monophyly UncertainMonophyly Uncertain[down<--]Homilopsocidea Interpreting the tree
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Containing group: Homilopsocidea


The family Lachesillidae contains more than 270 species in 20 genera distributed worldwide, with the greatest diversity in Central and South America.  About 50 species are known from North America, most in the genus Lachesilla.

These are medium-sized bark lice (adults 2-4 mm, nymphs 2-2.5 mm) with somewhat slender bodies.  Body colors are brown; wings are usually clear, with or without markings.  Lachesillids inhabit dead leaves, bark, grasses, foliage of conifers, and may also be found in stored food.



Lachesilliade (excluding genus Eolachesilla) is strongly supported by:

General Characters

How to Know the Family

Discussion of Phylogenetic Relationships

The subfamily and tribal relationships within Lachesillidae were established by Mockford and Sullivan (1986), and subsequent molecular studies have supported these relationships, with a few exceptions. The position of genus Eolachesilla (Eolachesillini) has been in question for a long time; molecular data show that it is more closely related to Elipsocidae (Johnson and Mockford 2003), and morphological data suggest that Eolachesilla may represent a separate family (Yoshizawa 2002).

The family Lachesillidae is closely associated with both Ectopsocidae and Caeciliusidae.  A study of 18S nDNA, and 12S, 16S, COI mtDNA (Johnson and Mockford 2003) found one species of Lachesilla is sister to Ectopsocus (Ectopsocidae), and a second study of 18S found 4 species of Lachesilla to be monophyletic and sister to the subfamily Caeciliusetae (Johnson et al. 2004).


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. Proceedings 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. & Sullivan, D.M. 1986. Systematics of the Graphocaeciliine Psocids with a proposed higher classification of the family Lachesillidae (Psocoptera). Transactions of the American Entomological Society 112: 1–80.

New, T.R. 2005. Psocids, Psocoptera (Booklice and barklice), 2nd edition: Handbooks for the Identification of British Insects. Vol. 1, Part 7. Royal Entomological Society, London, UK.

Smithers, C. N. 1996. Psocoptera. Pp. 1-80, 363-372 (Index) in Wells A. (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.

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. Lachesillidae. Version 25 March 2009 (under construction). http://tolweb.org/Lachesillidae/14471/2009.03.25 in The Tree of Life Web Project, http://tolweb.org/

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