ARTHROPOD A. 113 



like the lower pair. Many species are apterous, especially among 

 the females. Ocelli are frequently present. Some have an ex- 

 serted ovipositor. Earwigs (Forfieulidas) are armed with a caudal 

 forceps, and the crickets (Gryllidse), Mantidse, &c. have setaceous 

 appendages (cerci), which are common to both sexes, and are 

 supposed to be connected with the sense of touch. Besides these 

 ordinary anal appendages, there is in some one or two pairs of 

 stylets, occasionally, in the male, modified into hooks. 



In their internal anatomy the Orthoptera are very highly orga- 

 nized, and are considered to stand in the foremost ranks of 

 insects. None of them are aquatic in any stage of their existence. 

 Prisopus flabellicornis (Brazilian) is said, however, to spend the 

 day under water, attached to stones &c., and to fly about only at 

 dusk. 



The noise produced by male crickets and Locustidae (the females 

 are silent) is due to the anterior wings rubbing against each other 

 at a part where both are furnished with a rasp-like nervure ; while 

 in grasshoppers and locusts (Acridiidae) it is the posterior femora 

 rubbing against the anterior wings. In the former the males 

 are also provided with a talc-like spot at the base of the anterior 

 wings. 



In the cockroaches (Blattidaa) the eggs are deposited in a cap- 

 sule, which is carried by the female, and in which the larvae are 

 hatched. The Mantidae deposit their eggs in cases of a papery 

 texture divided into cells, which they make under stones or on the 

 twigs of plants. The Saltatoria generally place their eggs in the 

 earth, often forming clay-tubes for their reception. 



Except the Mantidse and omnivorous Blattidas, all are vegetable 

 feeders, and, being very prolific, frequently destroy the produce 

 of a whole district . The locust ( (Edipoda migratoria) is only too 

 well known. Earwigs are great enemies of bees, as well as being 

 herbivorous. 



The only special auditory organs in insects are found in Acri- 

 diidse (a small membranous expansion on each side of the meta- 

 tborax) and in Locustidse and Gryllidas (a similar membrane on 

 each of the fore tibiae). 



The cockroach (Periplaneta orientalis'), mole cricket ( Crryllotalpa 

 wtlgaris), cricket (Grryllus domestieus), locust ((Edipoda migra- 

 toria), [the North-American locust is Caloptenus spretus], and 

 earwig (Forficula auricularid] belong to this order. Grasshoppers 

 are of various species, and belong to Stenobothrus and (Edipoda, 

 but the latter genus is not found in England. The stick- and 

 leaf-insects are Phasmidas ; but .the anterior wings, resembling 

 leaves, are also found in certain Locustidas. 



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