1867.] 



DAWSON — ON PALAEOZOIC INSECTS. 



205 



imagination the trill and hum of insect life that enlivened the 

 solitudes of these strange old forests. 



Mr. Scudder has kindly furnished descriptions of these insects 

 as follows : — 



Fig. 2. 



" Platephemera antiqua Scudder; (Fig. 2.) — The direc- 

 tion of the principal nervures in this insect convinces me that 

 it belongs to the Ephemerina, though I have never seen 

 in living Ephemerina so much reticulation in the anal area as 

 exists here — so, too, the mode in which the intercalary nervules 

 arise is somewhat peculiar. It is a gigantic species, for it must 

 have measured five inches in expanse of wings — the fragment is a 

 portion of an upper wing. 



Fig. 6. 



" Homothetus fossilis Scudder ; (Fig. 3.) — At first sight 

 the neuration of the wings -^eems to agree sufficiently with 

 the Sialina to warrant our placing it in that family; but it 

 is very interesting to find, in addition to minor peculiarities 

 that near the base of the wing, between the two middle veins, there 

 is a heavy cross-vein from which new prominent veins take their 

 rise ; this is characteristic of the Odonata, and of that family 

 only. We have, therefore, a new family representing a synthetic 

 type which combines the features of structure now found in the 

 Odonata and Sialina, very distant members of the Neuroptera. 

 The fragment is sufficiently preserved to shew the direction, extent 

 and mode of branching of nearly every principal nervure. It is 



