Entomology : with special reference to its biological and economic aspects . cardiac valve. ANATOMY AND PHYSIOLOGY 117 Alid intestine (mesenteron) : ventriculus (stomach). Hind intestine {proctodcciun) : pyloric valve, ileum, colon,rectum, anus. Stomodseum.—The mouth, the anterior opening of thefood canal, is to be dis-tinguished from thepharynx, a dilatation forreception of food. Inthe pharynx of mandib-ulate insects the food isacted upon by the saliva;in suctorial forms thepharynx acts as a pump-ing organ, in the manneralready described. The (Tsophagns is com-monly a simple tube ofsmall and
Entomology : with special reference to its biological and economic aspects . cardiac valve. ANATOMY AND PHYSIOLOGY 117 Alid intestine (mesenteron) : ventriculus (stomach). Hind intestine {proctodcciun) : pyloric valve, ileum, colon,rectum, anus. Stomodseum.—The mouth, the anterior opening of thefood canal, is to be dis-tinguished from thepharynx, a dilatation forreception of food. Inthe pharynx of mandib-ulate insects the food isacted upon by the saliva;in suctorial forms thepharynx acts as a pump-ing organ, in the manneralready described. The (Tsophagns is com-monly a simple tube ofsmall and uniform cali-ber, varying greatly inlength according to thekind of insect. Passingbetween the commissuresthat connect the brainwith the suboesophagealganglion (Fig. 113), theoesophagus leads grad-ually or else abruptlyinto the crop or gizzard,or when these are absent,directly into the addition to its func-tion of conducting food,the oesophagus is some-times glandular, as in the grasshopper, in which it is saidto secrete the molasses which these insects Digestive system of a beetle, Carabus. a,anal gland; c (of fore gut), crop; c (ofhind gut), colon, merging into rectum; d,evacuating duct of anal gland; g, gastriccjeca; i, ileum; m, mid intestine; mt, Mal-pighian tubes; o, oesophagus; p, proventricu-lus; r, reservoir.—After Kolbe. Ii8 ENTOMOLOGY Fig. 147. The crop is conspicuous in most Orthoptera (Fig. 145) andColeoptera (Fig. 146) as a simple dilatation. In Neuroptera(Fig. 147) its capacity is increased bymeans of a lateral pocket—the food reser-voir; this in Lepidoptera, Hymenopteraand Diptera is a sac (Fig. 148, c) commu-nicating with the oesophagus by means ofa short neck or a long tube, and serving asa temporary receptacle for food. In her-bivorous insects the crop contains glucoseformed from starch by the action of salivaor the secretion of the crop itself; in car-nivorous insects this secretion convertsalbuminoids into assimilable peptone-likesubs
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectentomology, bookyear1
