Louse Any small, mean, annoying critter, but more especially the head louse 
a wingless, blood-sucking insect that frequently inhabits the scalps of children (and sometimes adults), where it causes itching and scratching. It can also raise the blood-pressure of frustrated parents, leading to outbursts of bad temper and swearing. Plural lice, as in rhymes with ‘not very nice’.
Louse-ladders Jackspeak (naval slang) for sideburns.
Lousy Infested with lice. Also feeling lousy, being irritable, listless and sullen, often accompanied by slightly raised temperature and flu-like aches, caused by the body’s immune response to multiple doses of louse saliva injected as an anticoagulant to prevent blood-clots during louse feeding.
Nit Insect egg, more specifically the egg of the head louse super-glued to a hair strand. Even more specifically, the empty egg shell which lingers longer than expected, causing unnecessary anxiety to school boards.
Nit-picker Mother (occasionally a father or older sibling) who grooms head lice from young ones. Also nit-picking, the act of careful, precise, patient and tolerant grooming.
Nitty-gritty Dust-dry louse faeces, often disturbed by the head-scratching louse-infested pupil struggling over reading, ‘riting and ‘rithmetic.
Nit-wit A dolt. Someone whose wits are dimmed by chronic allergic reaction to louse bites. Originally a simpleton whose low intelligence obviously attracted more head lice. Not to be confused with knit-wit, someone who tells jokes about knitting.
Nitty Nora The nit nurse. However, there are grave doubts that one was ever called Nora. There are also doubts that there were ever specific ‘nit’ nurses, just that school nurses’ other tasks have not been so immortalised.
No-nits policy Ill-advised guidelines for excluding from school children with empty louse eggs in their hair. Much easier to enforce than a no-living-lice policy.
Numbskull A nit-wit, one whose scalp has become desensitised, tight and numb in response to continued multiple louse bites during heavy infestations.
Phthiraptera Official, scientific name for the insect group which includes human head lice, and also the weird and wonderful lice of many other mammals and birds.
Phthirapterist Cool-sounding job title of a scientist who studies lice. A nit-picker.
Books and pamphlets
Adamson, J. 2011. Topsy & Tim Have Itchy Heads. London: Ladybird.
Bancks, Tristan. 2009. Bug Out. Mosman, New South Wales: Laguna Bay Books.
Bancks, Tristan. 2009. Lift Off. Mosman, New South Wales: Laguna Bay Books.
Buxton, P.A. 1939. The Louse: An Account of the Lice Which Infest Man, Their Medical Importance and Control. London: Edward Arnold & Co. Reprinted 1947. Long out of print, but second-hand or print-to-order copies are available.
Denny, H. 1842. Monographia Anoplurum Britanniae: Or, an Essay on the British Species of Parasitic Insects Belonging to the Order Anoplura of Leach… etc. London: Henry G. Bohn. Rare, even in specialist antiquarian bookshops, but the first major work on lice in English.
Dougherty, J. 2005. Niteracy Hour. London: Young Corgi
Ferris, G. F. 1951. The Sucking Lice. San Francisco: Memoirs of the Pacific Coast Entomological Society, Volume 1.
Kim, K.C., Pratt, H.D. & Stojanovich, C.J. 1986. The Sucking Lice of North America: An Illustrated Manual for Identification. State College, PA: Penn State University Press.
Simon, F. 1997. Horrid Henry’s Nits. Orion Children’s Books.
Smart, J. 1942. Lice. London: Trustees of the British Museum. First written at time of war, this pamphlet was reprinted in 1948 and 1954.
Burgess, I.F. 2004. Human Lice and their Control. Annual Review of Entomology 49: 457–581.
Maunder, J.W. 1983. The Appreciation of Lice. Proceedings of the Royal Institution of Great Britain 55: 1–31.
Websites
Nit Heads – The Wonderful World of Head Lice:
www.lousehead.wordpress.com
Richard & Justine’s very own lousy blog
Phthiraptera.info:
www.phthiraptera.info
The website of the International Society of Phthirapterists
(for louse specialists this one)
Tree of life – Phthiraptera:
www.tolweb.org/phthiraptera/8237
Collaborative collection of web pages examining animal biodiversity
NHS direct:
http://www.nhs.uk/Conditions/Head-lice/Pages/Introduction.aspx
Standard UK health advice and information on head lice.