CHAPTER Vlir 

 ORDER ORTHOPTERA* 



Grasshoppers, Crickets, Cockroaches, and others 



The winged members of this order have two pairs of wings; the fore 

 wings are more or less thickened, hut have a distinct venation; the hind 

 wings are folded in plaits like a fan when at rest; there are many forms 

 in which the wings are vestigial or even wanting. The month-parts are 

 formed for chewing. The metamorphosis is gradual (paurometabolous) ; 

 the nymphs are terrestrial. 



The order Orthoptera includes some of the veiy common and best- 

 known insects. The most famiHar representatives are the long-homed 

 grasshoppers, locusts, crickets, katydids, and cockroaches. 



With the exception of a single family, the Mantidae, the members 

 of this order are as a rule injurious to vegetation; and many species 

 are quite apt to multiply to such an extent that their destruction of 

 plant life becomes of great economic importance. 



The two pairs of wings of the Orthoptera differ in structure. 

 The front wings are leathery or parchment-like, forming covers for 

 the more delicate hind wings. These wing-covers have received the 

 special name tegmina. The tegmina usually overlap, at least at the 

 tips, when at rest. The hind wings are thinner than the tegmina and 

 usually have a broadly expanded anal area, which is folded in plaits 

 like a fan when at rest. Many Orthoptera have vestigial wings, and 

 many are wingless. In the males of the Saltatorial Orthoptera, the 

 Locustidse, the Tettigoniidae, and the Gryllidae, musical organs have 

 been formed by modifications of certain parts of the wings; these 

 have been described in Chapter II. 



The mouth-parts are of the mandibulate type, that is, they are 

 formed for chewing. The mouth-parts of a locust are figured on 

 page 42. 



In the Orthoptera the metamorphosis is gradual, paurometabo- 

 lous. In the case of those species in which the wings of the adult are 

 either vestigial or wanting, the adults resemble very greatly immature 

 insects. It is often important to determine whether a short-winged 

 specimen is an adult or not. Fortunately this determination can 

 usually be made with ease with the Saltatorial Orthoptera, the 

 Locustidae, the Tettigoniidae, and the Gryllidae. In these three families 

 the wing-pads of the nymphs are inverted, as shown by the curving 

 down of the extremities of the wing-veins, instead of up as with the 

 adult; and the rudimentary hind-wings are outside of the tegmina, 

 instead of beneath them. The development of the wings of a locust 

 is described in Chapter IV, p. 175. 



*0rth6ptera: orthos (dpdos), straight; pteron {irrepbv), a wing. 

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