Nu. 1411. AMERICAS I'ALKOZOIC INSECTS— llAyDLIRlSCH. 689 



A portion of the thorax with the wing pads and some renniants of 

 the abdominal segments. The well-preserved pad of the hind wing 



A 



/ 



Fig. 16.— (Pal/Kodktyuptekon) virgimanum. 



shows a strongh' arched upper margin and an almost straight posterior 

 border. It has a length of about 12 mm. 

 Holotype.—Q^X. No. 25635, U.S.N.M. 



Order PROTODONATA (Brongniart) Handlirsch. 



(lenerally large insects, whose slender l)ody very (|uickly recalls 

 that of the odonates. The four equal wings are independent of each 

 other and movable only in a vertical direction; at rest, horizontally 

 outspread. The neuration of the wing is more highly specialized b}^ 

 the coalescence of several longitudinal yeins in the basal portion of 

 the wing, by the conversion of longitudinal veins into the so-called 

 accessor}^ sectors, and by the regular arrangement of cross veins. 

 Intersection of the longitudinal veins, pterostigma, "wing triangles," 

 as well as the reduction of the anal veins, which are quite generally 

 present in the odonates, are still entirely wanting in the present group. 

 The head is large, with large eyes, and powerful mandibles; the thorax 

 is constructed like that in the odonates, with much reduced tergites 

 of the meso- and metathorax, on account of which the wing bases 

 appear to be nearer together. The legs are strong, similar in form, 

 and of normal length; the antennas short. Unfortunatel3% in no speci- 

 men has the end of the abdomen yet been found, so that at present 

 nothing can be said as to the nature of the appendages. 



There is indeed no doubt that this group constitutes a connecting 

 link between the pahcodictyopteres and the odonates, combining the 

 characters of the two orders. 



The protodonates emlirace the largest fossil insects yet discovered 

 (length of wing over 300 mm.), and are found principally in the 

 younger beds of the Carboniferous of Europe and America. 



