. Outlines of zoology. Zoology. 3>6 PER1PATUS, MYR10P0DS, AND INSECTS. their superficial resemblance to those which are nauseous, a few strike "terrifying attitudes," while others are like pieces of plants. But for our purpose it is perhaps more important to recall the differences between the respiration of some laroe and that of the adult, between the apneustic larva of the dragon-fly and the holopneustic winged adult. Likewise of great importance, and supplying a basis for classification, are the changes in connection with the mouth organs (see p. 306). Internal metamorphosis.—I
. Outlines of zoology. Zoology. 3>6 PER1PATUS, MYR10P0DS, AND INSECTS. their superficial resemblance to those which are nauseous, a few strike "terrifying attitudes," while others are like pieces of plants. But for our purpose it is perhaps more important to recall the differences between the respiration of some laroe and that of the adult, between the apneustic larva of the dragon-fly and the holopneustic winged adult. Likewise of great importance, and supplying a basis for classification, are the changes in connection with the mouth organs (see p. 306). Internal metamorphosis.—In Insects with no marked metamorphosis, or with merely an incomplete one, the. Fig. 139.—Development of blow-fly (Calliphora erythrocephala). —After Thompson Lowne. The lower figure (A) shows the adult larva (maggot). Note, as compared with the caterpillar, the absence of appendages, except those about the mouth; h., the large hooks connected with the maxillae ; j>L, pro-legs. The upper figure (B) shows the pronymph removed from the pupa- case. In the abdominal region the imaginal discs are shown ; /., rudiments of legs ; w., of wings. organs of the larvae develop gradually into those of the adult. But in Insects with complete metamorphosis there is a marvellous internal reconstruction during the later larval, and especially during the quiescent pupal stage. Most of the larval organs are disrupted and partially absorbed by amoeboid cells, their debris being used in building new structures. Parts of larval organs which have not been highly specialised form the foundations of new adult structures. Of special importance are certain ingrowths of the larval skin (the epi- or hypo-dermis) which. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Thomson, J. Arthur (John Arthur), 1861-1933. Edinburgh, Glasgow
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Keywords: ., bookauthorth, bookcentury1800, bookdecade1890, booksubjectzoology
