Barklice, Booklice, and Parasitic Lice

Order Psocodea

The Barklice, Booklice, and Parasitic Lice (Order Psocodea) includes 435 species across 37 families and 90 genera in our directory.

About Barklice, Booklice, and Parasitic Lice

Psocodea includes ~11,000 described species of booklice, barklice, and parasitic lice. Booklice (Psocoptera) are among the most common household insects, thriving in humid environments where they feed on mold and fungi.

Economic Impact

Head lice (Pediculus humanus capitis) affect an estimated 6-12 million children aged 3-11 in the U.S. annually (CDC). The U.S. lice treatment market is valued at over $1 billion per year.

Ecological Role

Barklice are important decomposers that feed on algae, lichens, and fungi on tree bark. They help recycle nutrients in forest ecosystems. Parasitic lice have co-evolved with their hosts for millions of years, providing insights into host evolutionary history.

Families in Psocodea (37)

Species in Psocodea (435)

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Aaroniella badonneli

Philotarsidae

"Was first described from Sukhumi on the Black Sea coast and from Tbilisi. It is supposedly holarctic, but I am not so sure. It is entirely parthenogenetic and probably gets around rather readily on imported plants. Danks found it in abundance on B

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Aaroniella maculosa

Philotarsidae

Identification: Usually keyed by marking on lateral thorax. "Thoracic pleura marked with a single broad, dark band". This distinction is not always easy to determine. If the specimen is male, it is more than likely to be A. maculosa since this is the

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Bertkauia crosbyana

Epipsocidae

Identification: Body in general shades of brown, but there is considerable variation in body markings. This species has a much wider range than Bertkauia lepicidinaria.

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Bertkauia lepicidinaria

Epipsocidae

Identification: To quote Chapman: "Vertex suffused with brown which deepens anteriorly, a large median U-shaped mark of pure orange; remainder of head dark brown ...Antennae dark brown. Thorax dull white above; ... Abdomen dull white marked with brow

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Blaste opposita

Psocidae

Identification: Two large black wing spots "opposite" each other (one on bottom, one on top). The only species in our area with that trait. Metylophorus noavescotiae has marks in these areas but completely different head marking and is larger. Ptycta

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Blaste osceola

Psocidae

Identification: "...this may be Blaste osceola because of the smudge along vein Cua1 in the forewing. It is only slightly developed in the male, but it is present. The pterostigma is more extensively dark than in most of my specimens, but there is a

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Blastopsocus goodrichi

Psocidae

Identification: Forewings unmarked, hypandrium with a pale triangular mark.

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Booklouse

Liposcelis bostrychophila

Liposcelididae

Claimed to be the commonest NA booklouse, though other spp. may be going under this name . Although it undergoes obligate parthenogenetic reproduction, there is considerable variability in populations in domestic and commercial facilities. Morphologi

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Camelopsocus hiemalis

Psocidae

Identification: Male with pale brown wash posterior to pterostigma and in cellCu2.

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Cat Biting Louse

Felicola subrostratus

Trichodectidae

Cat Biting Louse (Felicola subrostratus) is a species in the family Trichodectidae, belonging to the order Psocodea (Barklice, Booklice, and Parasitic Lice). It is classified within the suborder Psocomorpha. This species belongs to the genus Felicola

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Cerobasis annulata

Trogiidae

Identification: Note long winglets with brown spotting (Ed Mockford, pers. comm.)

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Clinopsocus nigrescens

Elipsocidae

described from specimens collected in San Leandro, CA on old wooden boards in a garage by Joyce Gross

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Echmepteryx (Thylacopsis) madagascariensis

Echmepteryx madagascariensis

Lepidopsocidae

our only representative of the pantropical subg. Thylacopsis Enderlein, that contains 17 spp. total, known mostly from tropical oceanic islands

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Ectopsocus briggsi

Ectopsocidae

Identification: E. briggsi and E. californicus are difficult to distinguish except on a slide even when you have them on hand, and photos are much more difficult. Apparently now, E. briggsi has become established in spots along the east coast, so tha

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Ectopsocus californicus

Ectopsocidae

Identification: The very distinct dark spots on the wing and the dark postclypeus are diagnostic. (E.L. Mockford, pers. comm. to =v=) But note comment on briggsi info. page: "E. briggsi and E. californicus are difficult to distinguish except on a sli

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Ectopsocus pumilis

Ectopsocidae

Ectoposcus pumilis was described by N. Banks in 1920. In he female, the apical processes of the subgenital plate are well sclerotized and have a short acuminate spike at the tip. Se Figure 81j in Charles Lienhard (1998)

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Elipsocus hyalinus

Elipsocidae

" E. hyalinus in North America is restricted to the Pacific coast. It is much more widespread in Europe and most of its relatives seem to be European, so I strongly suspect it was introduced from Europe." --E.L. Mockford, pers.comm. to =v=, 6.ii.2013

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Embidopsocus bousemani

Liposcelididae

Identification: Keyed based on anatomy and sclerotized structures of the thorax, phallosome, spermapore, spines on fore femur.

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Embidopsocus laticeps

Liposcelididae

Identification: "The flexuous, dark transverse lines on terga 4-6 and the broad head are diagnostic" -E.L. Mockford

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Graphopsocus cruciatus

Stenopsocidae

Identification: wing markings and vein patterns distinctive Females tend to be brachypterous, males macropterous ( Greenwood 1988 )

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Hemipsocus chloroticus

Hemipsocidae

Identification: "Note M-Cu crossvein in forewing" --Ed Mockford

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Indiopsocus ceterus

Psocidae

Identification: Very close to Indiopsocus texanus. Distinguished by subtle differences in the phallosome and subgenital plate. Was confused with Indiopsocus lanceolatus before that was recognized as a distinct species.

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Indiopsocus lacteus

Psocidae

Identification: Dets. D. Young, male & female Type Locality: Texas, Hays, San Marcos: Thousand Oaks Loop (spmn in the INHS)

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Lachesilla fuscipalpis

Lachesillidae

Identification: The hypandrium of the male is very distinct (See E. L. Mockford. 1993. North American Psocoptera Fig. 643). The subgenital plate of the female resembles Fig. 62 in A. Badonnel. 1971 (1972?). Psocopteres edaphiques du Chili. Bulletin d

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Lachesilla nubiloides

Lachesillidae

Identification: Forewing marked as in L. nubilis , but paler. Dorsal abdominal rings paler. Male epiproct with two elongate, blunt processes.

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Lachesilla penta

Lachesillidae

Identification: Subgenital plate has narrow terminally pigmented arms that curve inward and a flat truncated posterior margin like that in Fig. 202 in ; sternum 9 w/flattened oval pigmented area surrounding the spermapore [Fig. 642 ]; females of L. p

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Lachesilla perezi

Lachesillidae

Identification: The male genitalia can be observed with a dissection microsocpe at 60-70X. The structure matches Fig. 19 in the print reference listed below.

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Lachesilla punctata

Lachesillidae

Identification: Forewings marked as L. nubilis . Head and thorax pale to medium brown, middle of vertex and frons, median eye borders, and postclypeus medium brown, remainder pale brown; thoracic notal lobes medium brown. Surrounding cuticle pale, th

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Larger Pale Booklouse

Trogium pulsatorium

Trogiidae

"Not very common in [the US], seems to be restricted to the northeastern quadrant, and is found primarily in rather old, not very well maintained buildings." (Ed Mockford, pers. comm. to =v=, 16.ix.2009)

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Lithoseopsis hellmani

Amphientomidae

Known only from females. First found on limestone outcroppings near entrance to Ezel's Cave

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Loensia moesta

Psocidae

Identification: The black speckles all over the forewing are nicely diagnostic. When compared to the similar genus Trichadentecnum you will see that Loensia lacks the arc of 6 spots in the last 1/4 of the wing (one in the base of each cell). The very

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Metylophorus barretti

Psocidae

Identification: a lot of variation in wing markings (per E. Mockford) Type Locality: Districo Federal, Mexico

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Metylophorus purus

Psocidae

Identification: pterostigma completely clear, with white and black border; rectangular black marks between the eyes

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Myopsocus adventive-established-california

Myopsocidae

I have not yet worked on the identity of that myopsocid on the Pacific coast. I [...] will let you know the results when I do. (E.L. Mockford, pers.comm. to =v= 16.ii.2013)

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Myopsocus antillanus (Mockford)

Myopsocus antillanus

Myopsocidae

All females collected so far. Possibly parthenogenetic.

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Myopsocus minutus 0

Myopsocus minutus

Myopsocidae

Identification: This is the smallest myopsocid in North America. The pigmentation pattern on the forewing pattern in Figure 814 in North American Psocoptera (Mockford 1993). In this species the anterior margin of the forewing has a inward curve.

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Pachytroctes neoleonensis

Pachytroctidae

Known from males and apterous females. Arizona specimens are duskier than the Texas and Mexican specimens but do not differ otherwise.

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Peripsocus madidus

Peripsocidae

Identification: note the phallosome Det. D. Young, 2019 possibly the most prevalent psocid in the USA! … Diane Young, 28 October, 2018

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Peripsocus pauliani

Peripsocidae

Identification: forewing markings faint but distinct enough to separate from congeners; vertex lacks dark marks ( vs P. madidus )

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Peripsocus potosi

Peripsocidae

Identification: Forewing pattern distinctive: Fig.239 in earliest record in our area: FL 1983

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Peripsocus subfasciatus

Peripsocidae

Identification: No cubital loop (a U-shaped vein on the top-middle of the forewing) narrows down the families. Smokey gray wings => Perispocus The gray triangles at the wing tips (distal forewing) don't have a clear rectangle at their center.

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Polypsocus corruptus

Amphipsocidae

Identification: Males have longer wings and a white crescent half way along the wings, while the females have a clear line running down the distal edge of the wings, and they do appear about 1/4 shorter then they are. In addition females hold their w

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Pseudocaecilius tahitiensis

Pseudocaeciliidae

Identification: similar to P. citricola , differing in the following: reddish brown band as strong on head before and behind eye as on thorax, forewing (Fig. 257) with brown spots at distal ends of Rs and M branches, spot through areola postica at ac

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Psocus leidyi

Psocidae

Identification: A row of three black dots running across the middle of the forewing; large black dot on the 'nose' and strong black dot over the ocelli also distinctive

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Ptycta polluta

Psocidae

Identification: scalloped brown marks along the upper last half of the forewing (m1,m2,m3); markings continue down the center of the wing to the white and brown pterostigma

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Rhyopsocus celtis

Psoquillidae

Identification: Head and pronotum marked as in Fig. 7 . Compound eyes black. Remainder of head pale beige with a brown band from antennal base to compound eye and three small brown spots in middle of facial region, indicating positions of ocelli. Ant

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Rhyopsocus quercus

Psoquillidae

Identification: Sexes identical. Head and pronotum marked as seen here and here . Compound eyes black, but cobalt blue in freshly preserved specimens; remainder of head beige with grayish-brown subcuticular pigment granules along median ecdysial line

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Soa flaviterminata

Lepidopsocidae

Identification: Body and wings dark brown with a row of yellow setae at the distal end of forewings.

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Speleketor flocki

Prionoglarididae

Third known locality and first capture outside cave described here: Uhey, D. and Kendall, D., 2020. Third Known Locality for the Booklouse Speleketor flocki Gurney1 Found in Big Gypsum Valley, Colorado. Southwestern Entomologist, 45, pp.297-299.

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Stenocaecilius antillanus

Caeciliusidae

Identification: forewing very long and narrow, pale yellow with light pigmention notal lobes, a line along median ecdysal line and a spot in the middle of frons.

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Stenocaecilius casarum

Caeciliusidae

Identification: The elongated eye shape and dark mark through the frons and postclypeus are diagnostic Source: E.L. Mockford, pers. comm. to =v= 10.vii.2010

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Stimulopalpus japonicus

Amphientomidae

accidentally introduced during the late 1940s (DC area), now spread west to IL-AL

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Teliapsocus conterminus

Dasydemellidae

Identification: The fine hairs along the front half of the forewing, the big arching cubital Loop (a U-shaped vein on the top-middle of the forewing), and the bicoloured pterostigma are distinctive marks of this species ( comments here ).

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Trichadenotecnum majus

Psocidae

Identification: Six dark gray dots that form a backwards C in the last quarter of the wing, and the absence of fine black dots all over the wings suggests a female of this species. Can be found on sugar maples

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Valenzuela burmeisteri

Caeciliusidae

Identification: vein Cu2 in forewing with setae, antennae of moderate length

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Xanthocaecilius quillayute

Paracaeciliidae

Identification: "The eyes of living or freshly preserved specimens are pale green, wings dusky with distinct pattern of dark and pale veins X. quillayute ". The very similar X. sommermanae has yellow eyes but clear wings.

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