*0 FOSSIL IXSKCTS OK TIIK BRITISH COAL MKASTRKS. 



Prof. T. U. A. Cockerel] lias pointed out to me that the familv name was 

 originally wrongly written " Pteronidia-," and that the generic name was ante- 

 dated by I'li'i-nnii'li.'n, Rolnver, I'.Ml. lie thinks that the ditTerenee is sufficient to 

 justify retention, although it is only a single letter ('Proc. U.S. Xat. Mus.,' vol. xlix. 

 p. -i<><), 1915). Ilandlirsch (' Revision Palao/.oischen Insekten,' I'.'l'.l, |i. \:>) has 

 made the same correction, hut seems unaware that Cockerel! forestalled him. 



Genus PTERONIDIA, liolton. 

 I'.ML', Pfi:niiiiil!n, Bnllmi. (juurt. Joiirn. Gi.'ol. Soc.. vol. Ixviii. p. :!!:;. 



Generic Characters. Wings three times as long as wide. Radial sector with 

 five simple, backwardlv directed twigs. Median dividing low down into two 

 principal branches, and ending on the inner margin in five twigs. Cubitus stout, 

 divided into two principal branches, the foremost with two twigs, and the hinder 

 ending in four. Interstitial neuration of thin oblique nervures. 



Pteronidia plicatula, Bolton. Plate I, fig. :! ; Text-figure ;2. 



IlU'2. Pteronidia ylicatula, Button, < L >nart. .loimi. (icol. Soc , vol. Ixviii. p. 31:!, pi. xxxii, HL;'S. I- -It. 



TI//II'. Incomplete wing ami impression; Moysey C'ollection, .Museum of 

 Practical Geology, .lermyn Stivet (nos. 30,-JiU and .'iO/J-J-j). 



FlQ. 2. Pteronidia plicatula, 'Bolton; ivst<.rati.ui f l''ft winy, natural sixt-. II i'Mh' ( 'c'.il Measures 

 below Top Hani Coal); Shipley Manor Claypit, Ilkeston, Derbyshire. Moysey Collection, Mvis 



i'racl. (icol i in is. ;J(),L'L']. ami ;!i).^.">). 



l/iiri::<in <m<l Lun/l it //. Middle Coal Measures (below the Top Hard Coal); 

 Shipley Manor Claypit, Ilkeston, Derbyshire. 



N//rr/'//V I 'liiintrfrrx. Wings triangular in outline, with subacute tip, strongly 

 plicated. Radial sector dividing into five simple twigs. Median with two prin- 

 cipal branches and five marginal twigs. Culiitus wide-spaced; two principal 

 branches, the inner doubly forked. 



/ V.-.T, i/i/iiiii. This is a long delicate wing, of which the outer marginal portion 

 and the base are missing. It was probably about- 7<> ""> mm. long, with a basal 

 width of L!< nun., reduced to S mm. near the tip. 



The outer margin must have been flatly convex, while the inner margin is 



