Entomology : with special reference to its biological and economic aspects . Tracheal capillary end-network from silk gland of Porthetria dispar. p, peritrachealmembrane; t, tracheal capillary.—After Wistinghausen. proach each other (Fig. 176) and during expansion theyseparate. The tergum moves more than the sternum in Cole-optera and Heteroptera, and vice \ersa in Acridiidse, Odonata,Diptera and aculeate Hymenoptera. The width of the abdo-men usually changes but little during respiration, for the ter-gal and sternal mo\ements are taken up by the pleural lucui- FiG. A B Transverse sectio
Entomology : with special reference to its biological and economic aspects . Tracheal capillary end-network from silk gland of Porthetria dispar. p, peritrachealmembrane; t, tracheal capillary.—After Wistinghausen. proach each other (Fig. 176) and during expansion theyseparate. The tergum moves more than the sternum in Cole-optera and Heteroptera, and vice \ersa in Acridiidse, Odonata,Diptera and aculeate Hymenoptera. The width of the abdo-men usually changes but little during respiration, for the ter-gal and sternal mo\ements are taken up by the pleural lucui- FiG. A B Transverse sections of abdominal segments, to illustrate respiratory movements. A,cockroach (Blatta); B, bee Woinbiis); s, sternum; t, tergum. The dotted linesindicate positions of terga and sterna after expiration; the continuous lines, afterinspiration.—After Pu^teau. hrones which, as in the grasshopper, infold at contraction andstraighten out at expansion. Other respiratory movementsoccur, but they are of minor importance. ANATOMY AND PHYSIOLOGY 139 Fig The rate of respiration increases or diminishes with theactivity of the insect and with temperature and other condi-tions. In six specimens of Mclaiiopltis differcjitialis, held l)e-tween the lingers, the thoracic spiracles opened and closedrespectively 34, 43, 45. 54. 60 and 61 times per minute. Fourindividuals of M. fcuuir-rubniiii under the same cir-cumstances gave 70, 78, 90and 92. At expansion inspirationtakes place, and at contrac-tion expiration occurs. Inthe grasshopper, the thoracicspiracles open almost simul-taneousl
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectentomology, bookyear1
