Annual report of the Board of Regents of the Smithsonian Institution . Figure 7.—Dragon flies of the suborder Anisoptera. When the insects are perched the wings areheld horizontally at right angles to the body the dorsal surfaces together. (Fig. 8.) Members of the Zygopteraare sometimes distinguished as damsel flies; most of them are ratherweak creatures with long, slim abdomens and slender wings narrowedat the bases. They are comparatively feeble fliers and are easilycaught. The true dragon flies of the suborder Anisoptera are sub-divided into two families, the Libellulidae and the Aeschnidae
Annual report of the Board of Regents of the Smithsonian Institution . Figure 7.—Dragon flies of the suborder Anisoptera. When the insects are perched the wings areheld horizontally at right angles to the body the dorsal surfaces together. (Fig. 8.) Members of the Zygopteraare sometimes distinguished as damsel flies; most of them are ratherweak creatures with long, slim abdomens and slender wings narrowedat the bases. They are comparatively feeble fliers and are easilycaught. The true dragon flies of the suborder Anisoptera are sub-divided into two families, the Libellulidae and the Aeschnidae. Thelibellulids are the common dragon flies seen about streams and pools,where they perch on the ends of twigs from which they dart out onvigorous short flights in pursuit of some small passing insect. Theaeschnids include those large species that we used to call Devilsdarning needles. Thej^ are most efficient fliers, being seldom seen anywhere as they go skimming above the surface of the water. HOW INSECTS FLY SNODGTIASS 391. and they often make long excursions inland, appearing in places wherea dragon fly is least expected. So agile are they on the wing that thacollector must sometimes resort to the gun and bird shot to procurespecimens of them. The May flies are members of the order Ephemerida. They aremostly fragile, short-lived creatures in the adult stage, and when atrest fold the wings straight up over the back with the dorsal surfacestogether. (Fig. 9.) All other modern winged insects, with a few exceptions such as thebutterflies, fold the wings posteriorly and horizontally over the bodywhen they are not in use. This man- ^^^^5t>^ ^^P? ner of folding thewings may be dis-tinguished a s is quite differentfrom the other, inwhich the extendedwings are merelybrought togethervertically over theback, and it involvesthe presence of aspecial mechanismof flexion which thedragon flies and Mayflies do not possess. Since the wing-flexor apparatus hasvery e
Size: 2650px × 943px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorsmithsonianinstitutio, bookcentury1800, bookdecade1840
