Entomology : with special reference to its biological and economic aspects . Imaginal buds of full grown larvaof Picris, dorsal aspect, b, brain;m, mid intestine; s^, prothoracicspiracle; S*-, first abdominal spiracle;sg, silk gland; I, prothoracic bud;II, bud of fore wing; III, bud ofhind wing.—After Gonin. DEVELOPMENT I8l nation. The six ventral buds form the legs eventually; ofthe dorsal buds, the middle and posterior pairs form, respec-tively, the wings and the halteres, and the anterior pair formthe pupal respiratory processes. Each imaginal bud is situ-ated in a pcripodal cavity, the wal
Entomology : with special reference to its biological and economic aspects . Imaginal buds of full grown larvaof Picris, dorsal aspect, b, brain;m, mid intestine; s^, prothoracicspiracle; S*-, first abdominal spiracle;sg, silk gland; I, prothoracic bud;II, bud of fore wing; III, bud ofhind wing.—After Gonin. DEVELOPMENT I8l nation. The six ventral buds form the legs eventually; ofthe dorsal buds, the middle and posterior pairs form, respec-tively, the wings and the halteres, and the anterior pair formthe pupal respiratory processes. Each imaginal bud is situ-ated in a pcripodal cavity, the wall of which {pcripodal incin-brane) is continuous with the general hypodermis; as the legsand wings develop, they emerge from their pcripodal sacs andbecome free. In Corcthra but little histolysis occurs, most of the larvalstructures passing directly into the corresponding- structuresof the adult. Corcthra, indeed, is in many respects interme-diate between heterometabolous and holometabolous insects as regards its internal changes. Fig. Section through left hind wing in larva of Pieris rapce, the section being a frontalone of the caterpillar; the base of the wing is anterior in position,, and the apexposterior, c, cuticula; h, hypodermis; t, trachea; w, developing wing.—After Mayer. Muscidae.—In ]Musci(ke, as compared with Corcthra, theimaginal buds are more deeply situated, the pcripodal mem-brane forming a stalk (Fig. 220), and the processes of his-tolysis and histogenesis become extremely complicated. Thehypodermis, muscles, alimentary canal and fat-body are grad-ually broken down and remodeled, and part of the respiratorysystem is reorganized, though the dorsal vessel and the centralnervous system, uninterrupted in their functions, undergocomparatively little alteration. The imaginal hypodermis of the thorax arises from thick- I82 ENTOMOLOGY Fig. 223 • enings of the peripodal membrane which spread over the lar-val hypodermis, while thelatter is gradually beingb
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectentomology, bookyear1
