. Insect pests of farm, garden and orchard . Fig. 22.—Ideal section through an insect: a, aUmentary canal; h, heart;n, nerve cord; s, spiracle; t, tracheal tubes; I, legs; w, wings. (FromRiverside Natural History.) 30 INSECT PESTS OF FARM, GARDj^N AND ORCHARD branous lips. These apertures arc called spiracles or stigmata(Fig. 21 sp.), and are the openings of the respiratory openings are to be found in all insects, though not soeasily seen in the adults. Connecting these spiracles is a pair oftubes on each side of the body, throughout its length, from whichbranch off smaller tube
. Insect pests of farm, garden and orchard . Fig. 22.—Ideal section through an insect: a, aUmentary canal; h, heart;n, nerve cord; s, spiracle; t, tracheal tubes; I, legs; w, wings. (FromRiverside Natural History.) 30 INSECT PESTS OF FARM, GARDj^N AND ORCHARD branous lips. These apertures arc called spiracles or stigmata(Fig. 21 sp.), and are the openings of the respiratory openings are to be found in all insects, though not soeasily seen in the adults. Connecting these spiracles is a pair oftubes on each side of the body, throughout its length, from whichbranch off smaller tubes to all of its organs and tissues. Fresh. n. sp Fig. 23.—Internal anatomy of silk-worm, from photo of Azoux Model:A, upper or dorsal bodywall seen from within; B, the back of the silk-worm removed, showing alimentary canal; C, alimentary canal removed,showing nervovis system and tracheal trunks; tr., trachea; , dorsalvessel or heart; ph., pharynx or mouth; su., supra-oesophageal ganglion;, spiracles or breathing pores; n., nerve cord; , trachealtrunk; oes., oesophagus or throat; cr., crop; , silk gland; pro.,provcntriculus; st., stomach; , hind intestine. air is thus inhaled to all parts of the body through these tubes(Fig. 21, tr). The l^lood of insects does not circulate through any system oftubes as it does in the higher animals. Along the middle of theback, above the alimentary canal, is a long tube popularly calledthe heart (Fig. 23, dv). This heart is composed of a number ofchambers, each of which is furnished with side valves foradmitting blood from the body-cavity. The blood cominginto the hea
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1915
