. Biology; the story of living things. THE POPULAR INSECT PLAN 209 -Salivary glarjcCS esophogors - - honay Stomach ..prov©ntricultC5 Digestion, Circulation, Respiration, and Excretion The digestive tract posterior to the crop has to do with the digestion of food. The stomach, a large cyhndrical structure, has a valvelike arrangement between it and the crop to prevent nectar not used as food from going further. It leads into a small intestine, which in turn expands to form the rectinn at the posterior ⢠end of the body. - (^'W'^'^ â - pl^^'^yn&al glands Attached to the an- x% '^-^A<a#-
. Biology; the story of living things. THE POPULAR INSECT PLAN 209 -Salivary glarjcCS esophogors - - honay Stomach ..prov©ntricultC5 Digestion, Circulation, Respiration, and Excretion The digestive tract posterior to the crop has to do with the digestion of food. The stomach, a large cyhndrical structure, has a valvelike arrangement between it and the crop to prevent nectar not used as food from going further. It leads into a small intestine, which in turn expands to form the rectinn at the posterior ⢠end of the body. - (^'W'^'^ â - pl^^'^yn&al glands Attached to the an- x% '^-^A<a#-P°stc«nlbml%iands terior end of the intestine is a circle of Malpighian tubules, about one hun- dred in number, named after their discoverer, Marcello Malpighi, who '^V^^^^^^'^^^-'J^f first pictured them in his Anatomy of the Silk- worm published in 1669. The tubules are excre- tory in nature, as is proven by the fact that small crystals of nitrog- enous wastes are formed in them. In the insects and crustaceans, there is no closed system of blood vessels as was found in the earthworm, but in the former there is a well-developed, dorsally placed, tubular heart, located in the abdomen and perforated by paired openings, or ostia, through which blood enters. Blood is forced out of the anterior end into spaces, or sinuses, which in the insects are found throughout the body cavity and take the place of blood vessels. The heart acts somewhat like a rubber bulb syringe in a pail of water, serving, along with the muscular movements of the insect, to keep the blood in motion through the blood sinuses. Snod- grass ^ shows that there is a rapid and complete circulation of blood through the main sinuses, the blood being forced backward into the abdomen on the ventral side of the body by the pulsat-. smdl intestine ventriculus. rectal gkncC The food tube of worker bee and glands con- nected with it. The pharyngeal glands form the royal jelly or brood food given to the larvae by th
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Keywords: ., bookauthorwalterherberteugeneb1867, bookcentury1900, bookpublish
