. Marvels of insect life [microform] : a popular account of structure and habit. Insects; Insectes. that thfv purify thdr bUxKi by means of L-ills which will be described later. ' ' As already pointed out in earlier pa^es the blood flows freely into all available spaces ol the body without being confined in arteries and veins ; therefore the ordinary apparatus "f lunKs. where alone the blood can be broueht into contact with the air to absorb its oxvuvn not be useful. I'nder such an arranire- mcnt every particle of blood would be brought m turn to the air ; in the Insect it is the
. Marvels of insect life [microform] : a popular account of structure and habit. Insects; Insectes. that thfv purify thdr bUxKi by means of L-ills which will be described later. ' ' As already pointed out in earlier pa^es the blood flows freely into all available spaces ol the body without being confined in arteries and veins ; therefore the ordinary apparatus "f lunKs. where alone the blood can be broueht into contact with the air to absorb its oxvuvn not be useful. I'nder such an arranire- mcnt every particle of blood would be brought m turn to the air ; in the Insect it is the ah that IS brought to the blood, no matter in what remote part of the body it ma-,- be This IS effected by means of a wonderful sv stem of elastic pipes into which the spiracles -pen. These pi[ known as trachea, con- .miialli- branch from the mains and subdivide into most minute ramifications like the \-i-ins of the higher animals. In their case the tubes are kept distended by the contained blood being continuously pumped through them with torce, owing to the unceasing and rhvthmical activity of the heart. The trachea of Insects """W bc-ing open to the exterior would collapse under the pressure of the internal organs but for the lart that they are strengthened bv a sninl antenna;, to the delicate of the 'egs. and into the muscles. Wherever they go thev arc bathed by the blood, and their texture '^ -" hne that the oxygen of the air passes tiireagh and is taken up bv the blood. In this »;av the necessity for an arterial svstem for ' irculating the blood is obviated. The circula- tion and renew-al of the air in these tubes is mamtumed by a rhythmical distension and ââ - ^n> Lirt-e Insivt between finger and thumb. ^'â¢"'"mso .Mâc,â op Water-beetle "", such a method docs not renew all the i,'"""' "'â ?;"*⢠»â â -â . i« rm^m photo^a,,!,,, ^" ^.t .,âce, as happens
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectinsects, bookyear1915
