Harvest Mite

A very tiny creature living in long grass but which can be carried into homes on clothing or the coats of dogs. Can give a very irritating bite.


Harmless spider-like creatures with eight exceptionally long, thin legs. They do not spin webs but occasionally wander into homes.

Head Lice

A medical problem more common since the development of “resistant” strains of lice.

The head louse is a blood-sucking parasite about 3mm long, greyish, but adapting to the hair colour of its host. The tiny, pearly eggs or “nits” are cemented to the hair close to the scalp and there are three nymphal stages. The eggs hatch in about eight days and the complete life cycle takes about 18 days.

The bites cause inflammation and itching, which leads to affected children scratching the scalp, introducing secondary infections such as impetigo or eczema, or literally feeling lousy.


Twice the size of the common wasp and brown and yellow instead of black and yellow. Builds nests in hollow trees and similar sites and individuals only occasionally enter houses.

House Dust Mite

Exceedingly common, minute creatures of the genus Dermatophagoides. The main source of the house dust allergens implicated in allergic, respiratory reactions such as asthma.

Feed on human skin scales and require both warmth and humidity. Mattresses and pillows provide ideal habitat.

House Fly

The Common Housefly and the Lesser Housefly are the most widespread household flies. The adult is 7-8mm long, grey in colour with black stripes on the back, with a single pair of veined membraneous wings.

The large compound eyes take up most of the head and are wider apart in the female than the male of the species. The smaller Lesser Housefly, rejoicing in the scientific name Fannia canicularis, is the one that cruises around light fittings, abruptly changing direction in mid-flight.

The Housefly has a sticky pad on each of its six hairy feet, and these enable it to walk upside down on ceilings or crawl up windows.

Houseflies complete their life cycle of egg, maggot, pupa, adult in a week during warm weather. The eggs are laid in batches of about 120 on rotting organic matter and the legless white maggots burrow into this food until ready to pupate in loose soil or rubbish.

The answer to “where do flies go in the winter?” is that some hibernate, but most pass the winter in the pupal stage. Houseflies may transmit a wide range of bacterial diseases.