. Parasites and parasitosis of the domestic animals : the zooÌlogy and control of the animal parasites and the pathogenesis and treatment of parasitic diseases . Domestic animals. ARTHROPODA 19. a weapon of defense provided with poison ii;lan(ls. P'roni its nature the sting is essentialh' onlj' possessed Ijy the females. Some insects on leaving the egg develop directly to the adult stage, the larva in most cases differing from the adult prin- cipallj' in the absence of wings. In such cases there is a slight change of form with successive molts, the wings being ultimately acquired. Here the met
. Parasites and parasitosis of the domestic animals : the zooÌlogy and control of the animal parasites and the pathogenesis and treatment of parasitic diseases . Domestic animals. ARTHROPODA 19. a weapon of defense provided with poison ii;lan(ls. P'roni its nature the sting is essentialh' onlj' possessed Ijy the females. Some insects on leaving the egg develop directly to the adult stage, the larva in most cases differing from the adult prin- cipallj' in the absence of wings. In such cases there is a slight change of form with successive molts, the wings being ultimately acquired. Here the meta- niorphic process is not thorough, and is therefore referred to as incomplete metamorphosis. The ma- jority of insects when hatched from the egg bear no resemblance to the adult, and there is no observ- able gradual approach to this form. The larva is characteristically worm-like and an active and vora- ^-^e bee, s^howing cious feeder, a number of molts occui'ring with the compound eyes, the increase in size during this stage. There then ^^^'^'' °celli, and the . , iv 1 1 1 1 IX J. antennee. â Magm- mtervenes between the larval and adult stages a fied (after Orton, by period of pupation, during which the animal is quies- Dodge; Copyright, 'cent and a series of changes ^^^tke'Sâ ""''" * occur m the body. At the conclusion of these changes the pupal case splits and the imago emerges, which, with the unfolding of the ap- pendages and hardening of the cuticle, has in all essentials developed into the complete sexual adult. In this form of development the changes are distinct, and the process is referred to as complete meta- morphosis (Fig. 8). The duration of life in insects, including the â stages of the egg, larva, pupa, and adult, usually does not extend beyond a year. With quite a number it is much shorter than this, while Fig. of terrai- with others it may be a nal segments of arthropod leg, matter of Several years. £..... Please note that
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectdomesti, bookyear1920
