Fig. 27.—Ephemeroptera. Hexagenia limbata, the nymphal form of the mayfly in [fig. 26]; in this stage the mayfly lives in water, emerging when full grown. Actual length about 1.0 inch.
The order is divided into two types; the adult flies are told apart as follows:
| Body stout, wings broad at base, the front and hind wings different in shape. Strong fliers. Dragonflies | Suborder Anisoptera |
| Body slender, wings narrowed at base, the front and hind wings similar in shape. Weaker fliers than dragonflies but nonetheless elusive. Damselflies | Suborder Zygoptera |
Fig. 28.—Odonata. Nymph of Anax junius, a dragonfly widely distributed in Illinois. Actual length of full-grown nymph about 2.3 inches. (Drawing courtesy of C. O. Mohr.)
Fig. 29.—Odonata. Tramea lacerata, a dragonfly commonly found near ponds and drainage ditches in Illinois. Wingspread about 3.2 inches. (Drawing courtesy of C. O. Mohr.)
Folding-Wing Insects
Almost all insects in this category can fold their wings in repose back over their bodies, as illustrated in [fig. 31]. A few kinds, notably some of the moths and butterflies, have lost this wing action and in repose hold their wings erect. In some of these kinds, the male is winged and the female is wingless; in others, certain generations may be wingless and others winged; and, in still others, the species may be wingless in all stages. No members of the orders of folding-wing insects molt after becoming winged or sexually mature.
