. Cassell's natural history. Animals; Animal behavior. CIRCULATORY APPARATVS UF IXSEcn: air, and by means of it the larviB are enabled to form protective coverings for theaist"lves, and especially to prepare the cocoons in which so many of them pass their pupal period of existence. A considerable portion of the interior of the body of an insect is occupied by a poculiar fatty substance called the adipose bodi/, which is especially abundant in the full-grown laivae, and consists of a yellowish, lobulated niiiss lining the walls of the body-cavity, and filling up the spaces between the visc
. Cassell's natural history. Animals; Animal behavior. CIRCULATORY APPARATVS UF IXSEcn: air, and by means of it the larviB are enabled to form protective coverings for theaist"lves, and especially to prepare the cocoons in which so many of them pass their pupal period of existence. A considerable portion of the interior of the body of an insect is occupied by a poculiar fatty substance called the adipose bodi/, which is especially abundant in the full-grown laivae, and consists of a yellowish, lobulated niiiss lining the walls of the body-cavity, and filling up the spaces between the viscenv. It would appear to be a , store of nutriment to be used up in the final maturation \ of the insects, as it often diminishes in volume in pro- portion as the reproductive organs are developed. The circidatory apparatus of insects is sufficiently simple. It consists of a sort of vessel running along the dorsal i)art of the insect, and divided by constrictions into a series of chambers corresponding in number with the segments of the abdomen, and then continued forward in the form of a simple tubular vessel (aorta), through the thorax to the head. The chambered portion part of this dorsal vessel is attaclied to the walls of the abdomen by a series of triangular muscles, which spring in pairs from a broad base on each side of each chamber, becoming narrowed towards the place of their attachment to the skin of the abdomen. The blood within the dorsal vessel is driven forward by the successive contractions of the chambers until it is forced out from the anterior orifice of the aorta, whence it returns through the iuter-spaces of the various organs (lacunce) to the abdomen again. It then passes into the sort of sinus fonaed around the dorsal vessel by its nmscles above described, and thence into the vessel itself through a series of valvular openings between the successive chambers, to be again driven out by the contrac- tions of the organ. There are consequently neither arteries
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Keywords: ., bookcentury1800, bookdecade1890, booksubjecta, booksubjectanimals
