. Smithsonian miscellaneous collections. idge of postnotum, or postscutellum; m,prealar hook of postnotum; n, postnotal apodeme; o, scapular hook. sculpture of the metasternum is minutely rectangulate. The punctureswhich occur are sparse, the hairs of medium length and more numer-ous laterally. The metathorax shows little specific and no sexual modifications. NO. lO MORPHOLOGY OF GNATIIOTRICHUS SCHEDL 41 THE ABDOMEN The chitinous skeleton of the abdomen shows little specific modifica-tion but it bears characters which are of importance in separatingthe higher groups. The differentiation is mai
. Smithsonian miscellaneous collections. idge of postnotum, or postscutellum; m,prealar hook of postnotum; n, postnotal apodeme; o, scapular hook. sculpture of the metasternum is minutely rectangulate. The punctureswhich occur are sparse, the hairs of medium length and more numer-ous laterally. The metathorax shows little specific and no sexual modifications. NO. lO MORPHOLOGY OF GNATIIOTRICHUS SCHEDL 41 THE ABDOMEN The chitinous skeleton of the abdomen shows little specific modifica-tion but it bears characters which are of importance in separatingthe higher groups. The differentiation is mainly in the number ofdorsal plates or tergites and the development of the spiculum ventralein the females. The structure and the relative proportions of the dif-ferent sclerites are illustrated in figures i, 2, 3, 20, 21, 22, 23, and 24. Dorsal plates or tergites.—All the tergites are normally covered bythe elytra. In the females seven and in the males eight tergites arewell developed. The first six tergites are more or less membranous. ^m /-\ ^ ._ I—^ ^1 /^-N9 Fig. 20.—Gnathotrlclms matcrlarius Fitch, male: Abdominal tergites, ventral aspect. I, 2, 3, 4, enlarged sections showing details of structure on the dorsal side; Epp, epipleurites;Epp 7 and 8 fused with tergites; Sp, spiracles; T, tergites. and flexible in both sexes, yellowish in color, and covered with spinousto toothlike armature on the external surface. The spinelike armatureis more medial and posterior on the plates. Near the anterior marginthe armature becomes more toothlike, forming broad plates armedwith minute spines posteriorly (figs. 20, Ti, 2,)- These plates nearthe median line on the second, third and fourth tergites are stouterand not so densely placed. In the same tergites there is a reductionof the chitinization, forming a membranous emargination. Stillanother type of armature is found on the pleurites as illustrated infigures 20, 4. The purpose of these armatures is doubtful. The in-tersegmental
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Keywords: ., bookauthorsm, bookcentury1800, bookdecade1860, booksubjectscience
