Spider are apparently absent. In some species, the exocuticle of the legs and prosoma is modified by a tanning process, resulting in brown coloration. Bilins are found, for example, in "Micrommata virescens", resulting in its green color. Guanine is responsible for the white markings of the European garden spider "Araneus diadematus". It is in many species accumulated in specialized cells called guanocytes. In genera such as "Tetragnatha", "Leucauge", "Argyrodes" or "Theridiosoma", guanine creates their silvery appearance. While guanine is originally an end-product of protein metabolism, its excretion can be blocked in spiders, leading to an increase in its storage. Structural colors
European nightcrawler and are pale yellow at first, becoming more brownish as the worms inside become mature. These cocoons are clearly visible to the naked eye. European nightcrawler The European nightcrawler, Eisenia hortensis or "Dendrobaena veneta", is a medium-small earthworm averaging about 1.5 grams each when fully grown. Generally blueish, pink-grey (cf. Latin "veneta" meaning "sea-blue") in color with a banded or striped appearance, the tips of their tails are often cream or pale yellow. When the species has not been feeding, it is pale pink. These worms are usually found in deep woodland litter and garden soils that are rich in