HEXAPOD INSECTS OF GREAT BRITAIN. 221 



present on the under surface of the front wing of the modern Gryllacris. He accordingly 

 referred the wing to the Orthoptera, and even to the Locustarian genus Gryllacris. This 

 view cannot possibly be maintained, and a more unfortunate comparison could hardly have 

 been made. Swinton himself acknowledges that he could not succeed in finding a species 

 of Gryllacris "with an effective hie," and the semblance of one he figures cannot be ascribed 

 to a stridulating apparatus ; for (1) the " file " he figures could not produce any sound when 

 brought into contact with a similar structure on the opposite wing, since from their course 

 the two would not be brought into the proper relations to each other, or at least into such 

 relations as they always are brought in stridulating Orthoptera ; (2) but it could not be 

 brought at all into contact with the similar part of the opposite wing, the wing-insertions 

 being far apart in Gryllacris, and the supposed file lying at the extreme base of a vein in 

 the middle of the wing; (3) if this were a stridulating organ, it would not only lie in a 

 different area from that in which it lies in all other Locustarians, but would agree with its 

 place in no other Orthoptera whatever. 1 



The supposed file in Gryllacris being no stridulating apparatus, any comparisons between 

 it and the fossil from this point of view are of course misplaced ; but, aside from this, the 

 position and course of the supposed file of the fossil is entirely different from that of the 

 supposed file in Gryllacris, more indeed as it really is in Locustarians. But a careful ex- 

 amination of casts of both obverse and reverse, kindly given me by Mr. Woodward, and 

 which show even more details than are given either by Swinton or Woodward (as, for 

 instance, the spiny nature of the edge of the costal margin), brings nothing to light which 

 lends any support to this supposition. 



In his comparison of the general neuration of the fossil wing and the modern Grylla- 

 cris, Mr. Swinton' s language is vague ; and his conclusion, though evident, is wholly 

 erroneous. It needs only the figures upon his plate to point out the essential differences in 

 the neuration. In the first place, a distinction of prime importance appears in the margin- 

 al vein, which forms the border (and is heavily spined) in the fossil, is widely removed 

 from it in Gryllacris, the mirgin being formed of a film supported by superior 

 offshoots from the marginal vein, which of course do not exist in the fossil. In Gryllacris, 

 the scapular vein is crowded into a narrow space, embracing on the margin only the 

 extreme tip of the wing ; while no such contraction appears in the fossil, where the area 

 embraced by this vein must cover the entire apical margin. The externomedian vein of 

 the fossil is closely crowded against the scapular at base, and parts from it beyond with a 

 sweeping curve (as in most Neuroptera), appearing as if a branch of it; while in Grylla- 

 cris it lies midway between the adjacent veins, an 1 has scarcely the slightest downward 

 tendency, its branches being equally parallel instead of divergent. The internomedian 

 vein in the fossil is widely separated on either hand from the adjoining veins ; while in 

 Gryllacris it is equally crowded with the others. Finally, all the branches of the latter, 

 as well as those of the preceding vein, impinge upon the apical margin in Gryllacris; 

 while in the fossil they strike the lower border of the wing. 



1 Mr. R. Etheridge of the British Museum has examined the is in fact only a fracture of the surface of the nodule, in 



original specimen and "is convinced that not the slightest which the wing is preserved. This is shown both on the fos- 



trace of any organ, as figured by Mr. Swinton . . . exists on sil and its counterpart." Geol. Mag. (2) vm, 298. note, 

 the specimen in question. The supposed ' stridulating organ' 



