Entomology : with special reference to its biological and economic aspects . Section through integument of abeetle, CJirysoboihris. b, basementmembrane; c^, primary cuticula; c,secondary cuticula; h, hypodermis cell;n, nucleus.—After Tower. ANATOMY AND PHYSIOLOGY 75 ecdysis is poured over the hypodermis by certain large specialcells, which, according^ to Tower. are not true glands, butthe setigerous cells which, in early life, are chiefly concernedwith the formation of the hairs upon the body; but upon the Fig. 89. \ ^. Modifications of the hairs of bees. A, B, Mcgachile; C, E, F, Collates;D,
Entomology : with special reference to its biological and economic aspects . Section through integument of abeetle, CJirysoboihris. b, basementmembrane; c^, primary cuticula; c,secondary cuticula; h, hypodermis cell;n, nucleus.—After Tower. ANATOMY AND PHYSIOLOGY 75 ecdysis is poured over the hypodermis by certain large specialcells, which, according^ to Tower. are not true glands, butthe setigerous cells which, in early life, are chiefly concernedwith the formation of the hairs upon the body; but upon the Fig. 89. \ ^. Modifications of the hairs of bees. A, B, Mcgachile; C, E, F, Collates;D, Chelostoma.—After Saunders. loss of these, the cell takes on the function of secreting theexuvial fluid, which is most copious at pupation. These cellsdegenerate in the pupa, and take no part in the formation ofthe imaginal ornamentation. Histology.—The chitinous cuticula owes its existence tothe activity of the underlying layer of hypodcnnis cells (). These cells, distinct in embryonic and often in early lar-val life, subsequently become confluent by the disappearance ofthe intervening cell walls, though each cell is still indicated byits nucleus. The cells are limited outwardly by the cuticulaand inwardly by a delicate, hyaline basement meiuhrane; theycontain pigment granules, fat-drops, etc. Externally the cuticula may be smooth, wrinkled, striate,granulate, tuberculate, or sculptured in numberless otherways; it may be shaped into all manner of structures, someof which are clearly adapti\c, \\hile o
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectentomology, bookyear1
