LIBRARY

CHAPTER XIX
16. Order CORRODENTIA 1 (Burmeister 1839) Comstock and
Comstock 1895
(Cor'ro-den'ti-a, from the Latin corrodens, gnawing.) German,
Flechtlinge. French, Psocides.
Psocids, Book Lice, Bark Lice, Dust Lice.
Minute to small, compact, apterous or alate, terrestrial insects with simple metamorphosis,
modified biting mouth parts; head large and free; antenna:) short or long and
filiform; compound eyes usually large and widely separated; ocelli absent or three in
number; prothorax small and neck-like; wholly apterotls, brachypterous, or with two
pairs of wings, hind pair nmch smaller than fore wings, venation simple; legs slender,
femora sometimes enlarged, tarsi two- or three-segmented; cerci absent.
This somewhat neglected order is composed of curious but homogenous
members which all look very much alike. Because of their small size, fragile
bodies, and their general saprophagous habits, they have had few entomological
admirers. A number of species have long been pestiferous and injurious in
houses, granaries, mills, warehouses, libraries, and museums, where they live
on cereal products, vegetable and animal debris, and on paste, glue, fungi,
dead insects, beeswax, and other organic substances. There is hardly a building
that does not harbor psocids, and they may literally swarm in mills, packing
houses. and food warehouses. It is not uncommon to buy packages of prepared
foods completely infested by these tiny, active creatures. They damage books 2
by eating away the paste and glue and often do considerable injury to botanical
and zoological specimens. To dried insect collections they are often very
destructive, and the entomologist must constantly be on the alert to protect
his specimens from them.
1 There has been a wide variance in the designation of this order of insects. Linmeus (1758),
placed them in the NEUROPTERA. In 1839 Burmeister erected the order COR RODENTIA
for the TERMITINA, EM BIDA':, CONIOPTERYGIDiE. and PSOCINA. Comstock and
Comstock (1895) restricted the name CORRODENTIA to the psocids and that now seems
proper, since all of the other groups included by Burmeister have been relegated to distinct
new or to other existing orders. COPEOGNATHA was not erected by Enderlein until 1903
and PSOCOPTERA by Shipley until 1904.
, The most important insects injurious to books are termites, beetles, psocids, cockroaches,
and the caterpillars of certain tineid moths. Of all these the beetles belonging to the family
ANOBIIDJE are the most important and include such economic species as Catorama herbarium
Gorham of tropical Africa, Dorcatoma biblioPhagum MagalM.es of Peru, Gastrallus laticollis
Pic of the Dutch East Indies, Neogastrallus liIJrinocens Fisher of Florida, Nico/Jium castaneum
hirlum IlIiger of Spain, and Sitodrepa panicea Linn. in many parts of the world. The last
named species, commonly called the drugsto're beetle is perhaps the most importanL destroyer of
books. "Book-worm" is a very indefinite and vague te':m that might be used for almost any
insect found in books, but there is no one specific species of that name.
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