404 OKTHOPTEEA. 



resembles that of the Conocephalinae (comp. antea, p. 374, and Tab. XIX. figg. 33, 34), 

 but with the axillary veins (#', #") at the base placed closer together and sometimes not 

 distinctly separated. There is always a central speculum, of elliptic, ovate, or piriform 

 shape. The tympanal field of the left elytron is frequently coriaceous, the speculum 

 itself being opaque. The tympanal field of the right elytron is coriaceous, but bears 

 always a large vitreous speculum ; it has no second (external) speculum, as visible in 

 the Conocephalinse (Tab. XIX. fig. 34, e). 



2. In the Group Pterochrozae the elytra are very wide and completely flat, exactly 

 imitating dead or living leaves ; they fold together like two sheets of paper, as in 

 the majority of the Lepidoptera Rhopalocera (only downwards instead of upwards), 

 the elytra not enveloping the body, but concealing it between their two flat surfaces. 

 In the males of the mimetic types (Pterochroza, Mimetica, Typophyllum, &c.) the anal 

 field is very small, and the tambourine bears a small piriform speculum. In the less 

 mimetic types, of green colour, the tympanal field is larger, and sometimes more or 

 less coriaceous in both elytra. 



3. In this group, as in the first, the elytra in repose form a cylindrical covering for 

 the body, but they are very differently constructed. In the males the anal field is very 

 large, wide, and extends nearly to the apex of the elytra, and it is modified in its whole 

 length, so that the tambourine extends over the entire field ; but the tambourine, 

 however, is not membranaceous, the whole of the anal field being semicoriaceous. The 

 second ulnar vein anastomoses with the anal vein, generally before the middle of its 

 length, and at this place the anal field is cut by a transverse fold or sulcus (which 

 extends also laterally across the ulnar area). The anal field is thus divided into three 

 parts : — The first part is small, and occupies the base up to the stridulating vein ; the 

 second part, placed between the stridulating vein and the transverse ridge, forms an 

 elongated square area which ought to contain the vitreous speculum, but this is 

 completely wanting, and the whole area is reticulated ; the third part, generally much 

 the longest, occupies the posterior half of the anal field, and it is furnished with 

 numerous approximate transverse veins, which perpendicularly pectinate the anal 

 vein. The last-mentioned portion of the anal field, although more or less coriaceous, 

 is, as well as the second portion, a sonorous field. In some species the male elytra are 

 swollen, forming an ample covering round the body, and very sonorous, the second 

 part of the tympanal field being extended very far back. The species of this section- 

 are confined to the Eastern Hemisphere, and form the groups Pseudophyllites and 

 Phyllomimites (' Sauterelles vertes,' Pictet and Saussure). 



We have omitted the genus Aprion from our enumeration, although one species, 

 A. (Acanthoprion) aztecus, has been described by us as from Mexico * ; we now have no 

 doubt that the insect was labelled with a wrong locality. 



* ' Sauterelles vertes,' p. 26, t. 3. fig. 21 ; Brunner v. W. Monogr. der PseudoDhvll. n, 77. 



