. Elementary text-book of zoology. Zoology. 538 INSECTA. as nervi respiratorii or transversi, is to be regarded as a true sympa- thetic. These nerves are given off near one of the ganglia of the ventral chain from a median nerve which runs between the two ventral nerve cords, has a root in the ganglion, and sometimes forms a small sympathetic ganglion. After their separation they again form lateral ganglia, the nerves of which pass into the lateral nerves, but afterwards separate again from the latter, and after forming plexuses supply the tracheal trunks and muscles of the stigmata. Of the Se
. Elementary text-book of zoology. Zoology. 538 INSECTA. as nervi respiratorii or transversi, is to be regarded as a true sympa- thetic. These nerves are given off near one of the ganglia of the ventral chain from a median nerve which runs between the two ventral nerve cords, has a root in the ganglion, and sometimes forms a small sympathetic ganglion. After their separation they again form lateral ganglia, the nerves of which pass into the lateral nerves, but afterwards separate again from the latter, and after forming plexuses supply the tracheal trunks and muscles of the stigmata. Of the Sense organs, the eyes* attain the highest grade of per- fection. The unicorn eal ocelli are principally present in larval life, but two or three of them are often present on the top of the head of fully-developed insects (fig. 87). The facetted eyes are placed at the sides of the head, and are found in the fully- developed insect (fig. 85). Auditory vesicles with otoliths have not been dis- covered in insects. Since, however, the capacity of perceiving sound can scarcely be doubted for numerous insects, and especially for those which are capable of producing sound, we are forced to presuppose the existence of some organ for the perception of sound. In fact', in the springing «>j>tcra apparatuses can be pointed to which probably serve as acoustic organs for the perception of sound waves. In the Acridice these are placed at the .--ides of the first abdominal segment close behind the metathorax (fig. 60, A), in the Gnjllodace and Locustidw in the tibite of the anterior legs, just beneath the articulation of the. FIG. 4-tK. — Tibia of the anterior ley femom /£„ 445 \ jn this region a tracheal trunk of Loeittttt a (after dilates between two lateral membranes so as to form ). Ty, >y vesicle, on which are spread out the end cells, pro- tympanic mem- brane with oper- vided with so-called nerve rods, of a nerve springing from the first thoracic ganglion (fig.
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1884
