SYNOPSIS OP THE ORTHOPTEEA OF WESTERN EUROPE. 183 



it, is a second weaker vein, Avhich is curved strongly, so that a smooth 

 area is enclosed; on the right elytron, the first strong vein is not seen, 

 and the area enclosed by the second vein consists of a perfectly smooth, 

 clear, transparent spot, like a piece of mica. This membrane acts as 

 the fiddle, while the upper elytron is the bow, when the insects 

 stridulate. Frequently the elytra are so abbreviated that only this 

 chirping organ is left, as in Olijnthoscelis, Leptophi/es, Poecilimon, etc.; 

 when this is the case the elytra of the females are reduced to mere 

 small lateral flaps ; in the Ephippigeridae, however, the elytra consist 

 of the stridulating organ only, in both sexes. 



The wings themselves are similar to those of the Acridiodea. The 

 sternal plates are free, and their form often offers important and useful 

 characters. In the head, the form, shape, and relative size of the 

 tubercle between the eyes is important. 



Perhaps the most important generic characters are afforded by the 

 legs ; the anterior coxse generally have a spine, the absence of which 

 characterise the Phaneropteridae. 



The number and arrangement of the spines on the femora and tibiae 

 are important. The shape of the tympanum on the anterior tibiae is 

 a useful character; this tympanum may be of three forms, as follows: — 



1. Open, " tympanum apertum,'' as in Meconema and many Phaneropteridae. 



2. Shell-shaped, or " tympanum conchatum," as in Tylopsis. 



3. Cleft-shaped, or " tympanum clausum," as in most genera. 



The tibife themselves may be cylindrical or compressed and sulcate. 

 The number of the apical spines on the tibife is a very important 

 character in this group. 



The tarsi are always four segmented ; in the Stenopehnatidae they 

 are laterally compressed, but, in other families, they are depressed, and 

 usually sulcate at the sides, except in the Phaneropteridae. In the 

 Decticidae, the first segment of the posterior tarsi has also a pair of 

 free lobes, called " plantulse." The genital apparatus affords also good 

 characters ; in the male we have the supra-anal plate of various forms, 

 and the cerci also are very varied ; the subgenital lamina sometimes 

 offers good characters, as also does the shape of the ovipositor of the 

 female, which is always exserted and compressed, but either straight, 

 ensiform, or falcate, strongly bowed, or gently curved. 



The ova are deposited by means of the long ovipositor in cracks in 

 grass, shrubs, trees, etc. and are laid separately, and not in oothecae. 



The larvae appear to undergo at least six stages. In general form 

 they resemble the imagines, but the colours are often different, and 

 nearly always brighter; the beginning of the ovipositor distinguishes 

 the female larva at an early stage ; the organs of flight are wanting, 

 but appear as lateral flaps in the nymph stage. 



Some groups are purely vegetable feeders, as the Phaneropteridae, 

 but others are voracious carnivores, as the Sagidae, Decticidae, etc., 

 while the Ephippigeridae seem to eat animal or vegetable food 

 indifferently. 



Their habits are very varied, but they prefer shrubs and bushes to 

 grass ; they are often found in beds of nettles ; hedgerow^s are favourite 

 haunts for the strong and active Decticidae : the Locustidae generally 

 sit and chirp ia thickets or nettle beds ; the smaller Phaneropteridae 

 crawl about in long grass, the Ephippigeridae sit and chirp in dense 

 thickets, whilst many of the Decticidae frequent the densest jungle. 



