338 A. H. Sivinton — On Fossil Orthoptera. 



■wing venation is in some measure preserved, but is somewhat 

 difficult to trace. The figure of it given by Heer, having been ob- 

 tained from the obverse of the impression, which retains the left 

 elytron intact, gives a little more of the cross venation. The G. 

 Charpentieri, figured by Heer, is by no means a perfect exposition of 

 this specimen. 



Gkyllacris (recent species). Under side of right elytron, see 

 Plate XIV. Fig. 1. 



The species of Gryllaeris are intermediate in character between 

 the crickets and swamp-loving leaf-crickets, the Locustina of 

 German authors, of which the great green grasshopper (X. viridis- 

 sima), so partial to our potato fields, is a familiar example. Their 

 haunt is the banks of the warm streams of India or Brazil. 

 MacLeay, on recording his capture of a specimen in such a situation 

 in Australia, remarked a mimicry in these insects to the Neuroptera. 

 Their enormous antenna, more than twice the length of the wing- 

 covers, are probably a protection. They carry their elytra folded in 

 a way peculiar to themselves. Thus while in the crickets we find 

 the marginal field of the elytron turned down at a right angle to 

 the remaining portion, and in the leaf-crickets the marginal and 

 intern omedi ate fields giving a character to the insect by their roof- 

 shaped attitude, in Gryllaeris the marginal field brings the inter- 

 nomediate over with it as far as the line described by the interno- 

 mediate vein, and causes the elytra to present a rounded or somewhat 

 hexagonal superficies at their base, in the position of repose, so 

 that the wing-covers are more inclined than those of the crickets, 

 and less inclined than in the leaf or tree-crickets. 



Figure 1 gives the notation of the veins on the system adopted by 

 Heer, which adm.its also of tabulation, thus : — • 



Mediastinal Tein (unimportant) Marginal field. 



1 and 2. Scapular vein (bifurcate) \ 



3. Externomediate vein > Internomediate field. 



4. Internomediate vein ) 



5 and 6. Anal vein (this vein presents two stems) ... Anal field. 



Having analyzed a tolerably complex form of elytron as to vein 

 branches, and noticed the primal character afforded by its folding to 

 constitute a case or cover for the hind wings, the task of examining 

 the character of fossilized elytra that may seem to have affinity with 

 those of Gryllaeris will be in some measure facilitated. 



Gryllaeris Ungeri (restored). See Plate XIV. Fig. 2. 



As the remains of examples of this genus from the Eocene strata 

 are fully described by Heer in his Insectenfauna, I will content 

 myself with some observations on the interesting profile of G. 

 Ungeri in the British Museum, of which Fig. 2 is an attempted 

 restoration. 



In this case we have the thorax, abdomen, head, antenna, wings, 

 legs, tarsi, claws, etc., of a probably extinct insect of the Saltatorial 

 Orthoptera, preserved on a slab of Eocene Tertiary grey-coloured 

 (freshwater) Limestone, associated with stems of rushes or other 



