Smithsonian miscellaneous collections . togenesis are described in detail by Munscheid, whopoints out that the transformation of the odonate labium and the re-generation of its muscles is comparable to the pupal metamorphosisin holometabolous insects, except that in the Odonata the process islimited to a single organ instead of affecting the entire insect, whichotherwise is hemimetabolous. The long quiescent transformationperiod apparently allows the regenerated muscles to become attacheddirectly on the new imaginal cuticle without the interpolation of asecond moult. 36 SMITHSONIAN MISCELLANEO
Smithsonian miscellaneous collections . togenesis are described in detail by Munscheid, whopoints out that the transformation of the odonate labium and the re-generation of its muscles is comparable to the pupal metamorphosisin holometabolous insects, except that in the Odonata the process islimited to a single organ instead of affecting the entire insect, whichotherwise is hemimetabolous. The long quiescent transformationperiod apparently allows the regenerated muscles to become attacheddirectly on the new imaginal cuticle without the interpolation of asecond moult. 36 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 122 Aside from the specialization of the labium, the principal adaptivecharacters of the odonate larva are the organs that serve for respira-tion. In the Anisoptera a spacious rectal sac contains six longitudinaltracheated folds of the walls which are the larval gills. The muscularapparatus of the rectum for the inhalation and exhalation of water be-comes also a means of locomotion by the forcible ejection of spurts. Papt Cer JT \\ Fig. 5.—Odonata; general features of larvae. A, Larva of Anax sp., labium in passive position. B, same, labium loweredand partly protracted. C, Crocothcmis servilis Drury, labium applied against theface. D, anisopterous larva, posterior segments and lobes enclosing the anus. E,Agrion virgo L., posterior end of body with gill lobes removed. F, Archilestesgrandis (Rambur), end segments of body and gill lobes. G, Agrion virgo L., endsegments and apical lobes. An, anus; Cer, cercus (cercoid) ; dl, dorsal gill lobe; Eppt, epiproct; Lb,labium; II, lateral gill lobe; Md, mandible; Papt, paraproct; sa, supra-anal lobe. of water. Zygopterous larvae are provided with three external gilllobes of various forms at the end of the body, one median and dorsal,the other two lateral, borne on basal plates surrounding the these caudal gills are thin lamellae (fig. 5 F), but they maybe sacciform, and in some species they are slender
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Keywords: ., bookcentury1800, bookdecade1860, bookidsmiths, booksubjectscience
