. Cassell's natural history. Animals; Animal behavior. t>rJiUCTVli£ OF THE UKTUorTEKA. 119 mill when pi-esent they are more frequently three than two in number. In the antenme we timl tlie same ditiereuce as in the llliynchota, these organs being either long and thin, generally thread- like or bristle-shaped, and composed of numerous joints, or small organs, consisting of two or three biisal joints and a bristle, which, however, may be jointed. In the structure of the thorax there is considerable diflerence, although the three seg- ments are genemlly separate. The prothorax is frequently o
. Cassell's natural history. Animals; Animal behavior. t>rJiUCTVli£ OF THE UKTUorTEKA. 119 mill when pi-esent they are more frequently three than two in number. In the antenme we timl tlie same ditiereuce as in the llliynchota, these organs being either long and thin, generally thread- like or bristle-shaped, and composed of numerous joints, or small organs, consisting of two or three biisal joints and a bristle, which, however, may be jointed. In the structure of the thorax there is considerable diflerence, although the three seg- ments are genemlly separate. The prothorax is frequently of large size, forming the principal part of the thorax as seen from above, but sometimes it is. much reduced, representing a sort of ring like nec-k ; the meso- and metathorax are well developed, iuid in the great majority of the species are furnished with a wings. These latter organs are entirely wanting in the parasitic forms that we refer to the order, and in a few members of other groui)s ; but in general we find four wings, which, however, differ greatly in texture. Thus in one large section of the order . tlie fore wings are of a leathery or horny consistence, generally forming protective coverings (tegmina) for the hind wings, which are more membranous, iuid in which the veins radiate from a central point to the margin, so that in repose the wings fold together after the manner of a fan ; whilst in another great division both pairs of wings are membranous, and serve organs of flight, and the veining of both pairs is more or less alike. The legs are very various in their character. Like the labium, the abdomen shows in its structure ' ^ ⢠⢠, "EAD .iND MOUTH ORGANS OF COCKROACH, traces of approximation to the ideal type of insects, {After Griffith ani Henfiey.) as in many cases this part of the body shows the whole number a, head i/rom te/oTey, a, antrnnaa cut o£E; it., enicra- J L J niiuii: c, eyes; d. clypeiis. b, under iwrtions. u, of elev
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