FROil THE COAL-MEASURES OE SCOTLAND. 61 



the nearly perfect remains of an Arachnide, Eoplirynus Prestvicii, 

 having both sides seen in the two halves of the same stone*. 

 I allude to this in order to stimulate geologists in the neigh- 

 bourhood of coal-fields to devote some time to splitting these 

 nodules of the " pennystone " ironstone, feeling assured they will 

 be well rewarded by finding king-crabs, Arachnides, Myriopods, 

 insects, ferns, fruits, and other fossil remains, which may serve to 

 enrich their own and the public museums, and increase our know- 

 ledge of the fauna and flora of the Carboniferous epoch. 



Owing to the large expanse of surface covered by the fossil insect 

 under consideration, only two of the four wings are well preserved ; 

 and of these two we have not the extremities, or the posterior 

 border of the hinder wing. 



The two best-preserved wings measure 2£ inches in length and 

 1 inch and 1| inch respectively in breadth, the hind wing being 

 the broadest, as is the case among the Orthoptera generally. 



The anterior margin of the fore wing is not well preserved; but 

 a careful examination brings to light the characteristic strong lon- 

 gitudinal vein running parallel with the fore margin, so necessary 

 for giving support to the wing in flight. 



This is followed by a second equally straight vein. 



The third vein is likewise parallel, but bifurcates near the ex- 

 tremity of the wing. 



The fourth vein is much curved, and gives rise to six branches, 

 three of which again bifurcate, and all bend outwards and back- 

 wards towards the hinder border of the wing. About 2 lines from 

 the base of this strong fourth vein it unites with a fifth short vein 

 at an acute angle, enclosing with the proximal border of the wing 

 a triangular space. This triangular area is observable in all four 

 wings, and appears to correspond exactly with a similar vein- area 

 in the wing of Gryllacris (Corydcdis) Brongniarti described by Mr. 

 A. H. Swinton in the ' Geological Magazine,' 1874, Decade ii. vol. i. 

 p. 337, pi. xiv. fig. 3, as " a vocal organ, and which in the Locusttd^ 

 appears to be greatly developed, and to be furnished with a series of 

 minute arches, which the insect causes to vibrate by moving one 

 wing across the other, as the fiddle-bow is moved across the strings 

 of the violin." 



This shrill- vein is by no means always developed as an organ of 

 sound in all the members of the Orthoptera ; but few are without 

 it in some measure. 



The other veins of the wing take their rise from the centre of 

 this triangular vein, and, branching into three and into two, ter- 

 minate in the hinder border. 



The venation of the hinder wing differs but little from that of 

 the fore wing, save in its greater depth, and consequently in the 

 prolongation backward of the hindermost veins. (See PI. IX. fig. 1.) 



The transverse veinlets which brace the principal veins together, 

 have a general rectangular arrangement, dividing up the wing into 

 a great number of chiefly square and oblong meshes. 

 * Geol. Mag. 1871, vol. via. p. 385, pi. xl. 



