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After a brief mastication, the food passes directly to the rumen. Here it is subjected to a churning movement that mixes and presses the contents of the rumen forward in the direction of the oesophageal opening, where it is ready for regurgitation. It is then carried back to the mouth, remasticated and returned to the rumen. This is termed rumination.
The cartilage closing this opening is pressed shut by the base of the tongue when the bolus of feed is passed back and into the oesophageal opening. The larynx may be compared to a box open at both ends. The several cartilages that form it are united by ligaments. It is lined by a mucous membrane. The posterior extremity is united to the first cartilaginous ring of the trachea.
Its nervous system comprises eleven ganglia, not counting the oesophageal collar, whereas in the perfect insect there are only seven: three for the thorax, of which the last two are contiguous, and four for the abdomen.
As far as I can judge from the dissection of the specimen preserved in alcohol, whose viscera were affected by being kept too long in that liquid, the nervous system consists of eleven ganglia, not counting the oesophageal collar; and the digestive apparatus does not differ perceptibly from that of an adult Oil-beetle.
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