THE ANIMAL KINGDOM 429 



are the only insects that undergo a molt after attaining func- 

 tional wings. 



Example: Ephemera simulans, occurs in large numbers, 

 usually late in June in the Great Lakes region. 



Order Orthoptera (Straight-winged). Crickets, grasshoppers, 

 roaches, katydids, etc. The wings, when well developed, 

 consist of a thickened anterior pair, straight and narrow in 

 outline, and a thin posterior pair, which when at rest is folded 

 in plaits under the anterior pair. The mouth parts are for 

 chewing. Metamorphosis is incomplete. Most of them feed 

 on vegetation and their destruction of plant life causes enor- 

 mous damage. Some, cockroaches, for example, are more 

 general feeders. 



Examples: Gryllus domesticus, the house cricket, an old 

 world species that has been introduced into this country; 

 Melanopus differ entialis, a large grasshopper, common in 

 Eastern United States; Periplaneta americana, the American 

 cockroach; Diapheromera femorata, the walking stick, lacks 

 wings; Stagmomantis Carolina, the praying mantis, feeds 

 principally on other insects and therefore has a positive eco- 

 nomic value. 



Order Odonata (odous, tooth). Dragonflies and damsel flies. 

 There are two pairs of membranous wings with marked veining, 

 the posterior pair as large as, or larger than, the anterior. 

 The mouth parts are for chewing and the metamorphosis is 

 incomplete. The eggs of American species are laid in water. 

 The maxillae and mandibles of the larva are provided with 

 sharp teeth. The labium of the larva is enlarged, jointed, 

 armed with hooks, and can be thrust out in front of the head to 

 seize prey. 



Examples: Anax Junius, a common dragonfly; Agrion 

 maculatum, a common damsel fly. 



Order Isoptera (Equal- winged). Termites. These are social 

 insects, comprising a number of castes, each caste including 

 males and females. They may be distinguished from ants, 

 which they greatly resemble, by the fact that the abdomen is 

 joined to the thorax by a broad connection. (In ants this con- 

 nection is slender.) There are usually two pairs of long narrow 

 wings which are shed by the adult sexual males and females 

 after the nuptial flight. The intestine of some termites contains 



