THE 



GEOLOGICAL MAGAZINE. 



NEW SERIES. DECADE II. VOL. I. 



No. VIII— ATJGXrST, 1874. 



I. — Notes on Cektain Fossil Orthoptera claiming affinity 



WITH THE GENUS GrYLLACRIS. 



By A. H. SwiNTON, Esq. 



(PLATE XIV.) 



1 1. Gryllacris Ungeri, Heer. Figured and described by Heer 



Eocene Tertiary ... < in his Insectenfauna, 1849, s. 8, t. i. 



( 2. Gryllacris Gharpentieri^ Heer, op. cit. s. 12, t. i. 



i 3. Gryllacris lithanthraca, 2 species. Figured and described in 



Coal Formation ... < Palseontographica, bd. iv. p. 25 and 28, t. iv. 1-2. 



( 4. Corydalis Brongniarti, And. Buckland, vol. ii. p. 77. 



The above five insect remains, claiming affinity with the modern 

 genus Gryllacris, of the order Orthoptera, retain for the investigator 

 no characters in common, but such as may be afforded by the central 

 portion of the principal disk or internomediate field of the elytron, 

 and by the lesser marginal field. From comparison of these areas 

 in the specimens from the Coal-measures, as regards configuration 

 and venation, a certain similarity of design is observed, and a general 

 correspondence detected. By taking Heer's descriptions and figures 

 as data, this character is seen to be reproduced — less markedly dis- 

 tinct from the type observable in certain species of the modern genus 

 of Burmeister — both in the profile of G. Ungeri and in other frag- 

 ments preserved to us in the Eocene strata of the Continent. Com- 

 plete identification of these species must be the reward of future 

 investigators. 



The riaost perfectly preserved venation is presented by the frag- 

 ment of G. Brongniarti, hitherto reputed a Neuropterous insect, 

 closely allied to the living Corydalis of Carolina, and exhibited as 

 such by Audouin at the meeting of the Naturforscher at Bonn in the 

 month of September, 1835, but which Heer seems rather to indicate 

 as belonging to the Orthoptera ; and this latter view, it will I 

 think be seen, is quite agreeable to the venation and peculiarities of 

 construction exhibited in its wing, an object of undoubted beauty, 

 revealed by the fortuitous fracture of a nodule of Clay- ironstone, 

 and now preserved in the British Museum. The history of this 

 specimen is somewhat wrapt in obscurity. It was purchased by 

 Mantell at the sale of Parkinson's collection, the latter, there is 

 reason to suppose, having obtained it from the neighbourhood of 

 Colebrook-dale. It was subsequently transmitted to M. Brongniart, 

 and has been described by Audouin (Buckland, Geology and Mine- 

 ralogy, vol. ii. p. 77). In the Museum specimen of G. Ungeri the 



DECADE II. — VOL. I. — NO. VIIL 22 



