226 PROCEEDINGS OF THE ACADEMY OF [May, 



specimens of these fossil wings which, for reference here, I have 

 numbered as follows: 



No. 1. Labelled " Phenacolestes mirandus Ckll. Florissant," in 

 Professor Cockerell's handwriting; 27 mm. long from base to apex. 



No. 2. Labelled " Phenacolestes mirandus CkW. Florissant Sta. 12 B 

 (G. N. Rohwer)," in the same hand. Apparently a hind wing. 

 Distorted, length from base to apex as it lies on the stone 26 mm. 



Nos. 3 and 4. Unlabelled. [These are the two impressions of the 

 same wing, and were collected by Geo. N. Rohwer. T. D. A. Cock- 

 erell.] Apparently a front wing. Length of No. 3 from base to apex 

 28 mm. ; of No. 4 (apex lost) from base to distal end of stigma 25 mm. 



They are figured from enlarged photographs on Plate 'XIV as fig- 

 ures 1-4. 



The beautiful preservation of these wings has rendered possible 

 the drawing up of almost as full a description of the venation as for 

 any living species. 



Professor Cockerell has very kindly presented specimen No. 3 

 to the Academy of Natural Sciences of Philadelphia ; the other three 

 specimens will be returned to him. 



Thanks to the kindness of Dr. F. A. Bather, through the good 

 offices of Mr. C. J. Gahan, I have also studied two fossils of this 

 insect in the British Museum of Natural History, when in London 

 in August, 1912. One of these, catalogued as "No. I 8423," is the 

 paratype of Professor Cockerell's original description of Phenacolestes 

 mirandus. The other, "No. I 15,049," is labelled in Professor Cock- 

 erell's handwriting "Phenacolestes mirandus Ckll. Florissant Sta. 

 13 B (S. A. Rohwer)." No. I 8423 measures 20.5 mm. in length 

 from the wing-base to the proximal end of the stigma; the distal 

 part of the stigma and the tip of the wing are lacking; the nodus is 

 9 mm. from the base. No. I 15,049 has lost the stigma and apex of 

 the wing from the distal end of M2 forward (cephalad and distad) 

 and the extreme hind margin between the apices of M2 and Cui; 

 its length along the costa as preserved is 23 mm., the nodus is 10 mm. 

 from base. 



Use has also been made of an excellent photograph, for which I 

 thank Professor Cockerell and Dr. Max M. Ellis, of the University 

 of Colorado, of an almost perfect wing from the same locality as 

 that of the second specimen quoted in the preceding paragraph. 

 This photograph is reproduced as figure 5 on Plate XIV accompany- 

 ing this paper; it will be designated as No. 5 in these pages and 

 apparently represents a front wing. * 



