1S7S.] 125 



date. They have all been described* by Mr. Scudder, and respectively 

 named by bim : Xenoneura antiquorum, Gerephemera simplex, Plate- 

 phemera antiqwa, Lithentomum Hartti, Dyscritus vefiisfus, and Homo- 

 thetus fossilis. 



Xenoneura antiquorum and G-erepliemera simplex were obtained 

 from a lower portion of the shales than any of the others, and are, 

 therefore, presumably, the oldest of the six. The first named fossil, 

 X. antiquorum, appears to be the basal portion of a small wing, which 

 was probably about two inches in expanse. From the peculiar nature 

 of its neurationf, Mr. Scudder is of opinion that it represents an extinct 

 family of Neuroptera, and probably belonged to a group constituting 

 a synthetic type between the Orthoptera and Neuroptera ; he observes 

 that the most striking peculiarity in this specimen is the development 

 of apparently independent veiulets, forming portions of concentric 

 rings, at the base of the wings, which he compared to the stridulating 

 organ of some male saltatorial Orthopteron. Dr. Dawson;];, in alluding 

 to this peciiliarity in this specimen, remarks that, " nothing is more 

 "curious than the apparent existence of a stridulating or musical 

 " apparatus, like that of the cricket, in an insect otherwise allied to 

 "the Neuroptera. This structure also," continues Di-. Dawson, " if 

 " rightly interpreted by Mr. Scudder, introduces us to the sounds of 

 " the Devonian woods, bringing before our imagination the trill and 

 " hum of insect life that enlivened the solitudes of these strange old 

 " forests." 



The second specimen, G. simplex, consists of a fragment of the 

 tip of a large broad- wing, which appears to have belonged to a member 

 of the ^pliemerina. 



The third specimen, P. antiqua, is believed to be a portion of the 

 upper wing of a gigantic species of the Ejyhemerina, which must have 

 measured five inches in expanse of wings, and from its combination 

 of peculiarities 1 1 of structure, now only found in different groups, must 

 also be regarded as a " synthetic type." 



The fourth specimen, L. Hartti, is supposed to be a portion of 

 the lower wing of a Neuropterous insect, measuring about 3|- inches 

 in expanse of wings, and allied to the Sialina, but not belonging to 

 any family represented among existing forms. 



* Geol. Mag., vol. iv, pp. 387, 388 ; v, pp. 175, 176. Acadian Geol., aniea cit., p. 525, and 

 Dana's "Manual," anteo. cit., pp. 273, 274. 



+ Cf. J. W. Kirby, "On the remains of Insects from the Coal-measures of Duiham," Geol. 

 Mag., vol. iv, pp. 388 — 390, plate xvii. 



t Geol. Mag., vol. iv, 18»i7, p. 387, and Acadian Geology, pjj. 524, 525. 



II Mr. Scudder observes of this specimen : "the intercalary nervules, which in Ephemerina 

 "generally originate independently, arise here from a bent cross-vein, much as in Odonata." 

 Geol. Mag., vol. v, 1868, p. 175. 



