. The Australian zoologist. Zoology; Zoology; Zoology. 220 A RECLASSIFICATION OF THE ORDER Fig. 11.—The Nodus.—1.—Chlorocyphidae. 2.—Coenagriidae. 3.—Epallag- idae. 4.—Protanisoptera. Note the similarity between Figs. 2 and 4, pointing to a common origin for these two suborders. In the Protozygoptera, the origins of the two veins both lie somewhat distal to the level of the nodus, but as we follow the evolution of their undoubted descendants in the Zygoptera, we are able to follow the recession of these veins step by step until we arrive at a stage quite similar to that found in the
. The Australian zoologist. Zoology; Zoology; Zoology. 220 A RECLASSIFICATION OF THE ORDER Fig. 11.—The Nodus.—1.—Chlorocyphidae. 2.—Coenagriidae. 3.—Epallag- idae. 4.—Protanisoptera. Note the similarity between Figs. 2 and 4, pointing to a common origin for these two suborders. In the Protozygoptera, the origins of the two veins both lie somewhat distal to the level of the nodus, but as we follow the evolution of their undoubted descendants in the Zygoptera, we are able to follow the recession of these veins step by step until we arrive at a stage quite similar to that found in the Anisozygoptera. The proximal origin of Riv + and IRiii is basic for the whole of the Anisoptera, as well as for the higher and many lower forms of the Zygoptera, but we have no evidence that it was so for the Protanisoptera or their earlier descendants, if any. 5.—The Discoidal cell. (Part I, dc in all figures.) The discoidal cell, as a quadrangular space, open at the base, is similar in the Protozygoptera and Protanisoptera. In the former, however, we find it becoming acutely pointed distally in at least one species (Permolestes gracilis Martyn.), and it is so for the greater part of the primitive Zygoptera right up to the Megapodagriidae. In the Anisozygoptera, the discoidal cell of the forewing is of this same character, but that of the hindwing is a stage in advance and has taken on Anisopterous characters, that is to say, although originally typically Zygopterous in shape, it has evolved into one similar to that found in the Anisoptera. There is no evidence to show that the Protanisoptera deve- loped a Zygopterous discoidal cell from which the Anisozygopterous, dimorphic one, could have developed; on the other hand, that for the Proto- zygoptera could not be more Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perf
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