Pest Identification – Collections Care

This tool was developed by Preservation staff for use at University of Illinois libraries. The table contains information about bugs that commonly appear on traps in this area, including common and scientific name, adult and often larval images, and notes relating to the bug.

Name	Scientific Name	Approx. Size	Main Image	Alternate Image	Larvae/Nymph Image	Pest Category	Notes
Ant	Formicidae family	2-15 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Blunderer	This family covers a wide variety of any sizes and colors, but all are non-threatening to collections.
Ant, Flying	Formicidae family	2-15 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Blunderer	Flying ants have elbowed antennae, two pairs of wings of different sizes, and long legs (to differentiate from termites)
Bee, Yellow Jacket	Vespula or Dolichovespula	12-16mm				Danger to Humans
Beetle, Asian	Harmonia axyridis	5-6 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Blunderer	These beetles are unavoidable in the fall and early winter after soy crops are harvested.
Beetle, Cabinet (Warehouse)	Trogoderma angustum	2-4 mm	Image source: museumpests.net	Courtesy of "Mike Quinn, TexasEnto.net"	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Blunderer	These beetles are unavoidable in the fall and early winter after soy crops are harvested.
Beetle, Carpet	Anthrenus verbasci	2-3 mm	Image source: museumpests.net	Image source: museumpests.net	Image source: museumpests.net	Library/Museum Pest	Backs covered in colored scales. Larvae are particularly destructive and eat animal specimens, fur and feather, and woolen textiles.
Beetle, Cigarette	Lasioderma serricorne	2-3 mm	Image source: museumpests.net	Courtesy of Clare McLellan Museum Victoria	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Library/Museum Pest	Also called a tobacco beetle. Similar in appearance to a drugstore beetle, but has finer, more straight antennae and no lines on the back of their wing covers. Eat a wide range of dried plant materials including tobacco, but also known to eat animal proteins.
Beetle, Click	Conoderus bellus	2-6 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign[/caption]	Courtesy of the University of Illinois at Urbana-Champaign Library		Blunderer	Identifiable by the pointed protrusions on the corners of the thorax where it meets the abdomen. The larva are also called wireworms.
Beetle, Drugstore	Stegobium paniceum	2-3 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of Clare McLellan Museum Victoria	Courtesy of Simon Hinkley & Ken Walker Museum Victoria	Library/Museum Pest	Also called a biscuit beetle. Eat dried vegetable materials and cellulose, including tobacco, nuts, and dried plant specimens. Also noted to eat paper mache, some animal specimens and fungi.
Beetle, Furniture	Anobium punctatum	3-5 mm	Image source: museumpests.net	Courtesy of Clare McLellan Museum Victoria	Courtesy of Clare McLellan Museum Victoria	Library/Museum Pest	Wood borer, leaves gritty frass and bored exit holes about 1.5-2 mm in diameter. Prefer cool, damp conditions.
Beetle, Ground	Carabidae family	6-38 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Library/Museum Pest	Wood borer, leaves gritty frass and bored exit holes about 1.5-2 mm in diameter. Prefer cool, damp conditions.
Beetle, Hide	Dermestes peruvianus	7-10 mm	Image source: museumpests.net	Courtesy of Clare McLellan Museum Victoria		Library/Museum Pest	Eat leather and skins, but not generally good condition tanned leather. An infestation may indicate a dead rat/pigeon or other animal somewhere on the premises.
Beetle, Odd	Thylodrias contractus	1-4 mm	Image source: museumpests.net		Image source: museumpests.net	Library/Museum Pest	Only the males have wings. Eats dead insects and known to attack natural history specimens.
Beetle, Powderpost	Lyctus brunneus	5-6 mm	Image source: museumpests.net	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of Ken Walker Museum Victoria	Library/Museum Pest	Wood borer, leaves very fine talc-like frass. Tends to eat relatively fresh wood.
Beetle, Rove	Staphylinidae family	1-20 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Blunderer	Identifiable by short elytra (wing covers that typically hide the abdomen) and segmented abdomen.
Beetle, Spider	Ptinus tectus	3-5 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Library/Museum Pest	Feed on animal and vegetable detritus, can damage books, paper, textiles and wood if located near food. Frequently a sign of poor housekeeping or animal carcasses or nests in the vicinity.
Beetle, Weevil	Curculionidae family	3-10 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Blunderer	Most have a well-developed downward-curved snout; antennae elbowed, clubbed, and the first segment often fits into a groove in the side of the snout.
Book Louse	Psocoptera	1 mm	Image source: museumpests.net	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of Ken Walker Museum Victoria	Indicator	Feed on microscopic molds and can infest flour, paper and cardboard. Prefer warm, humid (above 60 % RH) environments.
Centipede, House	Scutigera coleoptrata	5-30 mm	Image source: museumpests.net	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Indicator	The house centipede, has an average of 17 pairs of very long, delicate legs and a rigid body. The legs also have dark stripes. House centipedes feed on spiders, bedbugs, termites, cockroaches, silverfish and other household pests.
Cockroach, American	Periplaneta americana	30-40 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Library/Museum Pest	Cockroaches are ubiquitous in campus environments and travel through steam tunnels under campus and into facilities closets. Cockroaches can damage library materials by chewing on them or excreting onto them, which causes staining. American cockroaches are the largest species found indoors in IL and are all brown with large wings.
Cockroach, German	Blattella germanica	10-15 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Library/Museum Pest	Smaller than the American Cockroach. Identifiable from other cockroaches by the two black stripes on the back of the thorax.
Cockroach, Oriental	Blatta orientalis	30 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Library/Museum Pest	Smaller than American Cockroaches. Identifiable from other cockroaches by the lack of wings and darker color.
Cricket, Ground .	Trigonidiidae Nemobiinae	5-12 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Blunderer	Crickets often "swarm" in the late summer and may enter buildings in large numbers, but pose no threat
Damsel Bug	Dicyphus hesperus	4-8 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the University of Illinois at Urbana-Champaign Library		Blunderer
Fly, Fruit	Drosophilidae family	3-4 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of Sarah McCaffrey Museum Victoria	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Blunderer	These are often a sign of poor housekeeping and unclean trashcans or rotting vegetable matter.
Fly, variable	Muscidae family	3-8 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Blunderer
Gnat	Anisopodidae family	3-6 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Blunderer
Leaf Hopper	Cicadellidae family	3-6 mm			Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Blunderer
Millipede	Diplopoda class	20-50 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Blunderer	Millipedes are commonly found during the Spring and Fall as they enter buildings from the outside. They can live in many different habitats such as mulched flower beds where moisture, humidity, and organic matter are high.
Minute Pirate Bug	Anthocoridae family	2-4 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the University of Illinois at Urbana-Champaign Library		Blunderer	Minute Pirate Bugs are most easily recognizable by the V shape their elytra (wing covers) make above the wings.
Mite, Predatory	Several	1 mm	Courtesy of the University of Illinois at Urbana-Champaign Library	Courtesy of the University of Illinois at Urbana-Champaign Library		Indicator	Predatory mites feed on other pests. Frequently, they are orange or red in color
Mite, variable	Several	1mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Indicator	Mites are an indicator of high-humidity environments. Most are non-biting, but some varieties can bite humans.
Mosquito	Culicidae family	3-10 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Blunderer	A nuisance that frequently follows staff and patrons into buildings in the summer months.
Moth, Clothes	Tineola bisselliella	10-20 mm	Image source: museumpests.net		Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Library/Museum Pest	Larva found in dark storage areas on fur, feathers, skins, wool and soiled textiles.
Moth, variable	Lepidoptera order	5-20mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign			Blunderer	Except for clothes moths, most common outdoor moths are blunderers into libraries
Noseeum (biting midge)	Several	1-2 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the University of Illinois at Urbana-Champaign Library		Blunderer	This often come into buildings on people who have traveled through the grass recently.
Pill Bug / Sow Bug	Armadillidiidae family	8-12 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign			Blunderer	Pillbugs can roll up into a tight ball when disturbed. Although they sometimes enter in large numbers, they do not bite, infest food, clothing, or wood. Since they require moisture, they do not survive indoors for more than a few days unless they are in very moist conditions.
Silverfish	Lepisma saccharina	5-15 mm	Image source: museumpests.net	Image source: museumpests.net		Library/Museum Pest	Associated with high RH (over 75%). Feed on microscopic mold, glue, ink, and starch. Grazers
Spider	Araneae order	5-40 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Indicator	Eats other insects. See identification guide for Brown Recluse spiders. Otherwise, usually harmless
Spider, Black Widow	Latrodectus mactans	3 -10 mm				Danger to Humans
Spider, Brown Recluse	Loxosceles reclusa	7-12 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign			Danger to Humans
Springtail	Entomobryidae family	1 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Image source: museumpests.net		Indicator	Springtails are carrion feeders that prefer high humidity. Very small and easily missed, they are best identified by their distinctive shape.
Termite	Kalotermitidae or Rhinotermitidae	4-7 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Library/Museum Pest	Winged and wingless (worker) termites have straight antennae and a long body with short lets. Winged termites have two pairs of wings of the same size and shape. Can infect timber and wooden objects as well as wooden structures. Dry wood termites can infest wooden objects.
Wasp, variable	Vespidae family	12-16 mm	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign	Courtesy of the Department of Entomology, University of Illinois at Urbana-Champaign		Danger to Humans	However can form hives inside buildings. If large population is observed, call about extermination and/or removal of nest.

Additional Pest Identification Resources

Borror, D., & White, R. (1970). A field guide to the insects of America north of Mexico. Houghton Mifflin Company.

Identification, Images, & Information for Insects, Spiders & their Kin for the United States & Canada. Integrated Pest Management. (n.d.). BugGuide. https://bugguide.net/

Milne, L., Milne, M., & Rayfield, S. (1998). National Audubon Society field guide to North American insects and spiders . A.A. Knopf. https://i-share-uiu.primo.exlibrisgroup.com/permalink/01CARLI_UIU/gpjosq/alma99405613012205899

Museum Pests Working Group. (n.d.). Identification Image Library. Museum Pests. https://museumpests.net/

Northeast Document Conservation Center. (2015). 3.10 Emergency Salvage of Moldy Books and Paper. Preservation Leaflets. https://www.nedcc.org/free-resources/preservation-leaflets/3.-emergency-management/3.10-integrated-pest-management