Psocoptera

Definition

An order (or suborder) of small, soft-bodied insects commonly known as barklice, barkflies, or booklice. Members have enlarged postclypeus with associated salivary glands for feeding on dry organic matter such as lichens, algae, fungi, and detritus; many species hold their wings roof-like over the body when at rest. Historically treated as a separate order, Psocoptera is now widely considered paraphyletic and has been subsumed into the expanded order Psocodea, which includes the former order Phthiraptera (parasitic lice).

Etymology

From Greek psōchos (to rub or grind) + ptera (wings), referring to the wing-rubbing behavior of some species.

Example

Graphopsocus cruciatus, a winged barklouse often found on tree trunks, exemplifies the outdoor-dwelling Psocoptera, while Liposcelis species are common domestic booklice that infest stored paper products and grain.

Synonyms

• Psocodea (in part)
• barklice (informal)
• booklice (informal)
• barkflies (informal)

Related Terms

• Psocodea
• Phthiraptera
• Paraneoptera
• Psocomorpha
• Troctomorpha
• Trogiomorpha
• Clypeus
• corrodent damage

Usage Notes

The name Psocoptera is increasingly treated as obsolete in modern taxonomy; contemporary literature typically uses Psocodea for the combined clade including both barklice/booklice and parasitic lice. When used, Psocoptera usually refers specifically to the non-parasitic, free-living members of Psocodea. The common names "barklice" and "booklice" are misleading, as these insects are not true lice (which are obligate ectoparasites). Contrast with Phthiraptera: Psocoptera are free-living, while Phthiraptera are parasitic.