. Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote. 538 IXSECTA. 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 supp
. Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote. 538 IXSECTA. 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 unicorneal 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 Ortlioptera 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 sides of the first abdominal segment close behind the metathorax (fig. 66, b), in the GryllodecB and Locustidce in the tibire of the FIG. — Tibia anterior legs, just beneath the articulation of the of the anterior femora /fig 445} In this region a trachea! trunk leg of lacuitii ' viritUfiima (after dilates between two lateral membranes so as to form y' a. vesicle, on which are spread out the end cells, pro- branewithopcr- vided with so-called nerve rods, of a nerve springing from the first
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