Spiders

The web-spinning spiders even if they see distinctly do not rely on sight to any appreciable extent. These males perform a tactile courtship through the medium of the web. As a rule the female recognizes the male's movements at once, and his court ship, a series of pluckings or jerks on the web, now serves to stimulate her and to entice her out from her retreat to a clear space where mating can take place.

As the season proceeds females of short-lived spiders usually lose much of their sexual impulse and are concerned solely with feeding and later with egg-laying. Males, their purpose served, are no longer recognized, and are often attacked and eaten.

Cocoons and Young.

All spiders make silken cocoons for their eggs, a fact which suggests that this was the first function of the silk. But in spite of the protection thus provided, the eggs are often infested with the larvae of parasitic Ichneumons and Diptera which eat them before they are hatched.

The . Lycosidae carry their egg-cocoons attached with silk to their spinners and are very concerned if one tries to remove them, resisting furiously. But if they are given some other object of about the same size as the cocoon, such as a pith ball, they will accept it even though it be brightly coloured ! Some taran tulas sit in the sun at the mouths of their burrows turning their cocoons slowly so that they receive light and warmth.

As soon as the young hatch, they scramble on to their mother's back and (as with all Lycosidae) cling on to her abdomen and are carried about for several weeks before they disperse.

Each minute spider climbs above its nest and then emits silk which is caught and drawn out by the wild. When the strand is long enough the spider seizes it with its legs and is borne away on the wind, often for a great distance. Such gossamer threads are a very beautiful sight on still days in autumn when they often cover whole fields.

In spite of their ingenuity shown in the construction of webs, burrows and nests of all kinds, spiders appear to have practically no intelligence. All their actions are instinctive. Even the con struction of the beautiful wheel webs is quite automatic, the severing of one strand of the spiral producing a corresponding deformity in the next. The Lycosid will accept a pith ball instead of her egg-cocoon, and a Theridion will industriously enwrap a piece of paper agitated with a needle point. (For classification of spiders, see ARACHNIDA.) (G. H. L.)