124 ME. H. BOLTON OX A GIANT DRAGON-FLY [June 1914, 



Affinities, — The broad longitudinal principal veins, with their 

 straight cross-branches, and the characters of the anal area form 

 typical Protodonate features, and there can be little doubt that 

 the wing belongs to a member of that group. Its relation si lip 

 seems closest to the genera Paralogies and Meganeura. The 

 genus JParalor/us of Scudder contains but one species — P. 

 cdsclmoides. 1 The specimen upon which the species was founded is. 

 incomplete, the tip of the wing being missing. It was restored by 

 Scudder, who gave a maximum length of 125 mm. to the complete 

 wing. This implies a much smaller insect than that to which the 

 Radstock wing-fragment belonged. 



A comparison of the Radstock wing-fragment with the proximal 

 third of Paralogies cesclinoides shows that there is a general simi- 

 larity, but a wide difference in detail. JP. cesclinoides does not 

 possess a free alar expansion on the anterior margin of the wing, nor 

 is there any trace of tubercular ornament. The costa and the sub- 

 costa are more widely separated than in the Radstock wing, the sub- 

 costa reaching the wing-margin beyond the middle of the length of 

 the wing. 



The cross-branching of the smaller veins is much the same in the 

 two wings. The main points of difference are the presence in the 

 Radstock specimen of tubercles along the main veins ; the remark- 

 ably robust character of the latter ; also the development of 

 marginal spines, and of a frontal coriaceous bar. It is, however, 

 with the members of the remarkable family Meganeuridse that the 

 Radstock wing-fragment seems to have the closest relationship. 



Meganeura monyi, the huge dragon-fly described by Brongniart 2 

 from the Stephanian of Commentry, possesses a powerful costal vein, 

 which does not reach the frontal margin until the middle of the 

 wing — the inner half of the frontal margin being occupied by a 

 free alar development of the wing-integument. This alar area 

 occupies the position which, in the Radstock specimen, is occupied 

 by the coriaceous tubercular bar. The costal vein in both is a 

 broad and powerful strap-shaped structure, which undoubtedly 

 reached to the wing-apex in the Radstock wing, and is known to 

 do so in M. monyi. In both wings the costa is separated by a 

 slight interval from a somewhat parallel and weaker vein, the sub- 

 costa. The sub-costa is a much weaker vein in M. monyi than in 

 the Radstock specimen, where it is little inferior in development to 

 the costa itself. 



The hinder pair of veins in the Radstock wing correspond very 

 closely indeed to Brongniart's 'Veins VIII & IX'; the twelfth 

 branch of the hinder vein in the Radstock wing also corresponds 

 to ' Vein X ' of Brongniart. In detailed structure the two wings 

 differ markedly. There is no evidence of anterior and posterior 

 spines in Meganeura monyi, nor of the extensive tuberculations 



1 ' Insect Fauna of the Rhode Island Coalfield ' Bull. U.S. Geol. Surv. 

 No. 101 (1893) p. 21. 



2 'Faune Entomol. Terr. Prim.' 1893, p. 521, & pi. xli, figs. 1, 4; also C. R. 

 Acad. Sci. Paris, vol. xcviii (1884) p. 833. 



