THE MITES MITES are widely distributed all over the world. Economically they are as important as the spiders. They are, as a rule, minute creatures and can only be studied adequately with the aid of the microscope. Many mites exhibit little differentiation of the body into regions. Their habits vary enormously and in consequence their structure is often extremely modified; the mouth-parts especially differ in accordance with their feeding habits, but differences in habitat are quite frequently reflected by the legs which may end in bristles, hooks or suckers. They may be blind or alternatively they may possess a variable number of eyes. The life-history usually shows a metamorphosis consisting of egg, larva with a reduced number of legs—a nymph may or may not be present—and the adult. Mites may be free-living and live either in the earth, sea or freshwater streams and ponds; or they may be parasites on other animals.
The snout-mites are soft-bodied animals with long legs and are able to run rapidly in pursuit of insects. They live in cold, damp localities, and in the winter may be found beneath fallen leaves. Some, the spinning mites, produce silk; some have beaks which contain needle-like mandibles. Big appendages carrying comb-like claws serve to capture
prey. The harvest mites attack man, causing severe skin irritation and inflammation; farm labourers are frequently attacked while gathering the harvest. The Red ‘Spider ‘of our gardens is really one of the spinning mites and should it occur in great numbers much damage to foliage may result. Another of the spinning mites is a parasite of birds.
The water mites are nearly all confined to fresh water, though some live in brackish water, and a few in the sea. The adult water mites are usually free-living, but one is parasitic and lives on the gills of the freshwater mussel. They are beautifully coloured—green, blue and yellow, and yellow and black being the more usual combinations. They are larger than the average run of mites. Many of them live in rapid streams; some are social and are found together amongst pond weeds. They are carnivorous in habit.