PHANEKOPTEEIN^E. 311 



The nervures of the elytra are very simple and similar in both sexes. The vena 

 mediastina is very short and often effaced. The vence humcralis and discoidalis are 

 contiguous, at least in their proximal part, slightly divergent in their distal part. The 

 discoidal vein, somewhat arcuated and subsigmoidal, is the principal one ; it divides 

 the elytron longitudinally into two fields. The vena media is fused at the base with 

 the discoidal Vein, and escapes about the middle, and is most frequently furcate. The 

 anterior vena ulnaris is straight, terminating on the sutural margin. The dorsal field 

 is coriaceous, punctured, or reticulated. This field, being the musical part of the 

 elytron, requires special attention. 



The typical dorsal field must be described from the females, it being unmodified in this 

 sex. It presents three veins : the anal vein, longitudinal and parallel to the ridge, and 

 two axillary veins, very feeble and frequently effaced. The second axillary vein, starting 

 from near the extreme base of the anal vein, is at first transverse, then breaks at an 

 obtuse angle to become longitudinal, more or less parallel to the sutural margin of the 

 dorsal field, and runs to near the end of the field to fuse with the end of the anal 

 vein. The first axillary vein is contiguous at the base with the anal vein ; it diverges 

 from this in its middle to become obliquely longitudinal, and anastomoses at its 

 extremity with the second axillary vein, delineating with this vein an elongated triangle. 

 In the females the dorsal field is generally very similar in both elytra and coriaceous, 

 except that the right elytron presents often along the sutural margin a more or less 

 wide membranaceous hyaline band longitudinally divided by the second axillary vein. 

 In the larger species (principally in the Steirodontites) this band is strongly reticulated 

 by transverse venules. We do not consider, however, that this membranaceous part is 

 to be regarded as a sort of stridulating tambourine ; probably it has lost its coriaceous 

 nature through being covered and protected by the left elytron when at rest. Never- 

 theless, it should be mentioned that in the large species the second axillary vein, which 

 divides or limits the membranaceous area, as well as the transverse venulae impinging 

 upon it, are very thick and prominent, as if modified for a special purpose. 



Musical organ. — The males of the Phaneropterinse are all musicians, except those 

 with rudimentary elytra ; but as the musical organ is confined to the small dorsal 

 (anal) field it is much less developed than in the Gryllidse, and is far from furnishing 

 such clear characters for classification as in that family. On the contrary, it is very 

 similarly formed in all the genera of this group, and varies principally in having the 

 nervures more or less fused in the coriaceous reticulation of the dorsal field. 



The modifications of the latter to form the tympanum are somewhat analogous to 

 what I have described in the Gryllidse, but the tympanal field being very narrow, the 

 stridulating vein cannot be formed by the anal vein ; it is the first axillary vein which 

 is here transformed for that purpose. There are only two axillary veins, both much 

 thickened and deflexed, but not in the same way on both elytra, the tambourine of the 



