STRAIGHT-WINGED INSECTS 



689 



EARWIG 



Theforceps- 

 like append- 

 age at the end 

 of thit insect* t 

 body is said to 

 be used for 

 folding and 

 unfolding tht 

 ivingi 



STRAIGHT-WINGED INSECTS, OR EARWIGS, COCKROACHES, SOOTHSAYERS, 

 STICK-INSECTS, CRICKETS, GRASSHOPPERS, AND LOCUSTS 



BY W. F. KIRBY, F.L.S. 



THE insects of this order are less numerous in species than those of any other but the next, 

 and are easily recognised. The fore wings are usually of a leathery consistency, and the hind 

 wings are folded beneath them like a fan in the more typical families, though in 

 the Earwigs and Cockroaches a somewhat different arrangement prevails. In the 

 Earwigs, indeed, the wings are doubled back at the ends, and in the Cockroaches 

 the wing-cases, or " tegmina," as they are technically called, overlap. As a rule 

 these insects feed entirely on vegetable substances. The " Soothsayers" form an 

 exception, being carnivorous, though they are not parasitic, like the Ichneumon- 

 flies, but feed on fresh food ; and several species of Earwigs, Cockroaches, and 

 Crickets, especially those which are semi-domesticated, are omnivorous, and will 

 eat animal as well as vegetable food. These insects have an imperfect metamor- 

 phosis that is, there is no inactive pupa-state ; but the young, on emerging from 

 the egg, already possess a recognisable resemblance to their full-grown parents, 

 and their metamorphosis consists of a series of moults, before the last of which 

 rudimentary wings appear in those species which ultimately acquire these appen- 

 dages. A considerable number of species never have wings, a circumstance which 

 frequently renders it difficult to determine whether a specimen is fully developed. 

 The antennae are usually long, and the joints distinctly separated, but are very rarely feathered. 

 At the other end of the body we often find two long jointed organs, called " cerci." The jaws 

 are always furnished with strong mandibles. Many Grasshoppers and Locusts have a curious 

 arrangement on the shank of the front leg, consisting either of a round or an oval cavity 

 on each side, closed by a membrane, or of two long parallel slits in front. These are con- 

 sidered to be organs of hearing. The largest known insects belong to this order ; the proportion 

 of large or moderate-sized species is considerable ; and the smallest are probably considerably 

 larger than the smallest members of any other group. They are not numerous in temperate 



climates; there are only about fifty British 

 species, and most of the larger of these are 

 either naturalised species, or merely casual 

 visitors from abroad. 



The EARWIGS form the first family. Some 

 are wingless, but most have very short wing-cases, 

 under which very large wings, forming the most 

 beautiful feature of these otherwise unattractive 

 insects, are doubled and folded into a very 

 small compass. Some of the smaller species fly 

 readily ; but others, such as the COMMON EAR- 

 WIG, though furnished with ample wings, are 

 rarely seen to use them. The most conspicuous 

 organ of the earwigs is the curious forceps at 

 the extremity of the body, the use of which 

 does not seem to be well made out, though it 

 has been suggested that it is used for folding 

 and unfolding the wings. The forceps differs 

 very much in size and shape in different species ; 

 it is always larger in the male than in the 

 female, and often differently shaped. In the 

 common earwig the male forceps is flattened 

 and contiguous at the base, and rounded and 



Phut bj If. P. Dandt, F.Z.S. 



AMERICAN 



COCKROACH 



Common in many -wareAouses and now found in most farts of the 

 "world 



87 



