Chrysalis

Chrysalis, an insect in its resting or pupal stage, that which intervenes between the cateterpillar and the perfect insect. When the caterpillar is mature, it prepares for itself a kind of case, known as the cocoon; this is usually made by the spinnerets or spinning organs. After the last moult the insect enters into the resting stage during which the adult form is perfected. In some cases, however, as in the Muscidae (including the housefly), the chrysalis retains the last larval skin. The appendages of the caterpillar are often modified into the corresponding parts of the adult, but in other insects this is not the case: thus in the housefly (Musca domestica) the head and thorax are not developed until the chrysalid stage. The life of the chrysalis is maintained by the consumption of the food stored up in the "fat body" of the caterpillars. The habit varies greatly with different species: in some cases they are hung up in very exposed positions on trees or shrubs, to which they are suspended by one end by a belt round the middle, or in other ways; or they may be hidden in clefts of trees or buried among roots.