SUBPHYLUM III 



INSECTA 



809 



Scudder suggested, the lingering fragments of an expiring group. The genera 

 Gronicus Eaton (Fig. 1566); Palingenia Burm. ; Baetis Leach; and Ephemera Linn. 

 occur in Baltic amber, and the last-named is found also in the Miocene lake beds of 

 Florissant, Colorado. 



t Order 26. PROTODONATA Brongniart. 



Mostly very large Insects tvith large eyes and heavy jaws ; segments of the thorax 

 unequal; legs stout, homonomous. Wings suheqital, horizontally expanded and with a 



Fig. 1567. 



Meganenra monyi Brongn. Stei)lianian (Upper Productive Coal Measures) ; Commentry (Alliw), France. 



i/e (afti'r lii'ougniart). 



finely reticulated venation ; the hinder pair somewhat dilated totvards the base, ivithout 

 folds. Nodus, pterostigma, wing triangle, quadrangle, reduction of the anal vein, and 

 other characteristic wing structures of the trice Odonata are not developed in this order. 

 Sector radii and media probably not crossed. Abdomen slender. 



This group is of transitional character between the Palaeodictyoptera and the true 

 Odonata or dragon-flies. Its geological range is from the Coal Measures to the Trias, 

 and the several genera belonging to it are grouped under the families Protagrionidae, 

 Meganeuridae and Paralogidae. In all, less than a dozen species are known, only 

 three of which are North American. These last are referred to the genera Paralogus 

 Scudder, typified by P. aeschnoides from the Coal Measures of Rhode Island ; Palaeo- 

 therates Handlirsch, from the corresponding horizon in Pennsylvania ; and Tupus 

 Sellards, from the Permian of Kansas. The gigantic Meganeura Brongn. (Fig. 1567), 

 from the Upper Coal Measures (Stephanian) of Commentry, France, measured over 

 75 cm. across the extended wings. 



