Guide to the study of insects, and a treatise on those injurious and beneficial to crops: for the use of colleges, farm-schools, and agriculturists . twofilaments with the ventral gau-glionic mass, formed by theprobable union of several gau-(1 glia, and situated in the middleof the false cephalothorax. Thecontinuation of the nervous cord consists of seven abdominalganglia, with the commissures united into a single cord. The maxillary palpi, functionally, take the place of antenn;e,showing how one organ may perform the office of another in adifferent, group of animals. It is also evident that t
Guide to the study of insects, and a treatise on those injurious and beneficial to crops: for the use of colleges, farm-schools, and agriculturists . twofilaments with the ventral gau-glionic mass, formed by theprobable union of several gau-(1 glia, and situated in the middleof the false cephalothorax. Thecontinuation of the nervous cord consists of seven abdominalganglia, with the commissures united into a single cord. The maxillary palpi, functionally, take the place of antenn;e,showing how one organ may perform the office of another in adifferent, group of animals. It is also evident that the spidercombines in the same organ the senses of taste, smell and feel-ing, which are supposed in insects to reside in the two pairs ofpalpi and the antennae. Mygale and Scorpio stridulate. The alimentary canal is formed, according to Siebold, on twotypes. In the mites and spiders, the stomach is produced lat-. ARACHNID A. (;2i) erally into large coecul appendages (Fig. 622, alimentary canalof Tegenaria civilis ; a, stomach, with cceca ; c, liver ; d, renalorgan ; f, fat body), and then passes into a short, small intes-tine, going straight to the end of the body. In the Pedipalpes(Phryuidae and Scorpions) the intestinal canal is more simple,not having any coscal dilatations to the very small stomach. The salivary glands are often of large size, especially inIxodes, and are thus adapted to their blood-sucking habits,much saliva being needed to mix with their food. In thespiders and scorpions the liver is well developed and distinctfrom the intestinal tube, being in the spiders a brown or dirtyyellow mass filling a large part of the abdominal cavity andenveloping most of the other viscera. As during the growth of the }*oung spider the head is thrownback on top of the thorax to which it is thus most closely uni-ted, it follows that the simple eyes, from two to twelve innumber, are situated on t
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Keywords: ., bookcentury1800, bookdecade1870, bookpublishe, booksubjectinsects
