. Coleoptera : general introduction and Cicindelidae and Paussidae. ary membrane is fenestrated, and whendepressed the blood passes through itspores and thus reaches the heart.— The heart, according to Grraber, isnothing more than a regulator, an organfor directing the blood in a determinatecourse in order that it may not whollystagnate, or only be the plaything of aforce acting in another way, as, for ex-ample, through that afforded by the body-cavity and the inner digestive canal. Atregular intervals a portion of the bloodis sucked through the same, and then, bymeans of th
. Coleoptera : general introduction and Cicindelidae and Paussidae. ary membrane is fenestrated, and whendepressed the blood passes through itspores and thus reaches the heart.— The heart, according to Grraber, isnothing more than a regulator, an organfor directing the blood in a determinatecourse in order that it may not whollystagnate, or only be the plaything of aforce acting in another way, as, for ex-ample, through that afforded by the body-cavity and the inner digestive canal. Atregular intervals a portion of the bloodis sucked through the same, and then, bymeans of the anterior supply tube it ispushed onward into the head, whence it passes into the cavities ofthe tissues. The different conditions of tension under which themass of blood stands in the different regions of the body thencause a further circulation. Connected with the general system there appear to be smallerpumping apparatuses, by means of which a regular flow of bloodis kept up iu the limbs, wings, antennae, etc. (cf. Packard, Text-Book of Entomology, p. 402).. Fig. 8.—Circulatory appa-ratus of a beetle; ,alar valves; , cephalicganglion. (AfterBerlese.) The liesjnratory System. Burmeister (Manual of Entomology, p. 158) says:—Weshall find the respiratory organs of insects as complex and per-fectly developed as we have found their blood-vessels simple andimperfect. The relations between these systems appear to be inthem completely reversed, for the air-vessels intersect the insectbody as multitudinously as we find the blood-vessels do in thesuperior animals. There are no lungs, but the whole body ispervaded with air by means of trachea?, which are tubes of veryvariable size, those connected with the external openings, calledthe stigmata or spiracles, being the larger main channels. Fromthese latter smaller channels proceed, and from these againoriginates a network of still smaller tubes, forming ramificationsthrough all the organs inside the body. THE RESPIHATOKY S
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbeetles, bookyear1912
