312 OETHOPTERA. 



left elytron being differently formed from that of the right elytron, whereas in the 

 Gryllidee the two tambourines are similar. Indeed, the two elytra are not alike in 

 structure, this being due to the left elytron covering the right one in repose, and to 

 their having different functions. 



The neuration of the males is as follows : — 



1st. In both elytra the anal vein is unmodified, straight as in the females. 



2nd. Left elytron. — The first axillary vein is nearly straight, as in the females; but 

 it emerges from the anal vein earlier than in that sex, and emits an inner branch, the 

 latter being broken at a right angle, becoming quite transverse, and very much thickened, 

 swollen above, and bordered posteriorly by a deep furrow. This transverse tumid 

 nervure is the stridulating vein. Beneath it is very prominent, longitudinally sulcate, 

 and transversely strigose, to produce the stridulation by rubbing like a file upon the 

 right elytron. This enormous transverse vein is the fiddle-bow of the musical apparatus. 



The first axillary vein, after having furnished the stridulating vein, continues back- 

 wards in a longitudinal direction, and is very fine, as in the female, its post-axillary part 

 appearing thus to be a special vein (which may be called the first post-axillary vein). 



The second axillary vein originates near the anal vein ; it is at first strongly trans- 

 verse and prominent, but becomes oblique to anastomose close to the sutural margin 

 with the inner end of the stridulating vein, enclosing with this a convex, piriform, 

 coriaceous, punctured area, which is certainly sonorous *. It is thickened to support 

 the stridulating vein, and is frequently divided into two parallel branches. The angle 

 by which the second axillary vein joins the stridulating vein might be compared to the 

 anal knot of the tambourine of the males of the Gryllidse f. 



The second axillary vein, after having joined the end of the vena stridulans, runs 

 back outwards, and becomes transverse, parallel to the stridulating vein, and only 

 separated from it by the transverse sulcus, and anastomoses at a right angle with the 

 straight external branch of the first axillary vein. The second transverse vein, thus 

 formed, is generally stout and thickened, but not so much as the stridulating vein ; ' 

 from above it appears as a second stridulating vein, but it is not prominent beneath 

 and serves only as a strong support for the stridulating vein. Frequently it is 

 not distinct, but fused with the latter ; in consequence, the left dorsal field shows 

 either one or two transverse veins. — The second transverse vein sends from its 

 middle backwards a thin longitudinal nervure (2 a vena post-axillaris $), which joins in 



* The two axillary veins are here disposed very much as in the male Gryllidae (comp. Tab. XIII. fig. 22, cc, a;'). 



t The two axillary veins modified and anastomosed form together what Brunner v. Wattenw)'l terms the 

 vena plicata. This expression, although not based on homologies, is often very convenient for the diagnoses of 

 species. 



X This vein is the posterior, unmodified and fine end of the second axillary vein, and is less prolonged than 

 in the females. It looks like a branch of the second transverse vein or of the stridulating vein ; but, in reality 

 it is the second transverse vein which is formed by a branch of the second axillary vein. 



