\2G [November, 



The fifth specimen, D. vefiisfus, is represented by so small a frag- 

 ment of a wing, that Mr. Scudder considers it impossible to determine 

 the approximate size of the insect, or the family to which it belonged ; 

 though its characters are clear enough to shew that it was Neuropterous, 

 and to distinguish it, with certainty, from the other specimens. 



The last specimen, H. fossil is, consists of the greater portion of 

 the upper wing of an insect, which Mr. Scudder believes to be the 

 representative of another new family of Neuroptera, " synthetic in 

 "nature, combining features of the Odonata and /S/a/mff ;" and he 

 adds that though it is in a mutilated condition, the extent and char- 

 acter of every principal nervnre can be determined. 



Although these Devonian insects are the oldest specimens yet 

 discovered, and consequently belong to the oldest known species, the 

 families of which they were members had possibly existed for ages ; 

 and it must not be assumed that even their family types necessarily, 

 or even probably, represented the earliest forms of insect life. 



The appearance* of insects on the earth was probably syuchronousf 

 with that of land plants ; and as remains of this division of the vege- 

 table kingdom have been discovered in rocks belonging to the Silurian J 

 period, the existence of aland flora, long before the date at which these 

 Devonian insects lived, is proved. The fact of the existence of land§ 

 plants at as early a date as the Lower Silurian period, appears to me 

 to be an additional reason, to those previously given ||, for assuming the 

 prohahilify of the first appearance of insects at an earlier age than that 

 of the Devonian shales at " Pern Ledges." 



The other classes of animals, whose remains have been obtained 

 from the same beds as the insects before described, are the Crustacea^ 

 and the Annelida;** and the plant-remains include Sir/illaria, Stiijmaria, 

 Calamites, AsterophyUites, AnnuJaria, Psilopliyton, Cordaites, &c., and 

 ferns of the following genera : Ci/clopteris, Neuropteris, Sphenojjteris, 

 Eymenopliyll ites, Pecopteris, and some others undetermined. 



Although the number of species of animals and plants, immediately 



* It is not impossible, however, that insects may have appeared before land plants, 

 ■which were not absolutely necessary to the existence of groups similar in their nature to the 

 Odonata and Epfitmerina, as they are essentially carnivorous, and aquatic in their early stages. — 

 H. G. 



t The theory of the existence of insects at an earlier age than the Devonian period would, 

 however, be inconsistent with Hackel's opinion as to the date of the first ajipearance of the class. 

 See ante p. 3 of this vol. — H. G. 



t Dana's "Manual," antea cit. p. 245. "The origin of the world," by Dr. Dawson, F.R.S., p. 

 330, London, 1877; and Proceedings of the American Philosophical Society, vol. xvii, p. )(j3 

 (October, 1877). 



§ Remains of land plants have been obtained by Dr. Scoville, Dr. Rominger and others, from 

 rocks of Lower Silurian age. Proc. Amer. Phil. Soc, vol. xvii, antea cit. 



II Ante p 53 of this vol. 



"U Amphipi'ltis paradoxus, Eurypterun puHcaria, and Trilobita. 



** Shells of iSpirorbis. 



